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Elements of Agriculture 



FOR USE IN SCHOOLS 



JAMES BOLTON McBRYDE, C. E. 

VIRGINIA POLYTECHNIC INSTITUTE 






' ' .' '. *•. ^.^'-^ > 



RICHA\OND, VA. 

B. F. JOHNSON PUBLISHING CO. 

190 1 



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THE LIBRARY OF 

CON«RESS, 
Two CopiEa Received 

APR. 2 1901 

COPYRJOHT ENTRY 

CLX88 OyxXc N.. 

\ COPY a 



Copyright. 1901, by 
James Bolton McBryde 



Ail rights rescrvnl 



PREFACE 



The pressing need of some agricultural instruction in 
our public schools is generally admitted by all who have 
given due thought to the subject. Especially is this true 
in the Southern States, where the great majority of the 
population is engaged in agricultural pursuits, and where 
comparatively few students from the rural districts find 
their way to college. According to the census of 1900, the 
total population of the Southern States is about 23,000,000. 
Of this number the rural population makes up fully 75 per 
cent or more; in other words, about 17,000,000. The total 
number of persons enrolled during the session of 1898-'99, 
as students of agriculture in the land-grant colleges of 
the South was 1,777, or about .0001 per cent of the agricul- 
tural population. The number of persons receiving agri- 
cultural instruction outside of these colleges is so small as 
not materially to affe-t the result, and it is safe to say that 
of the agricultural population of the South not more than 
one person in 10,000 receives any schooling in agriculture. 
We have, then, the amazing spectacle of an agricultural 
community that is spending annually for its schools and 
colleges about $35,000,000, and yet giving instruction in 
agriculture to only one person in every 1*0,000 of the agri- 
cultural population. 

That there are still great difiiculties in the way of the 
work of agricultural education is freely admitted. The 
v/ant of thoroughly trained teachers, the need of more and 
better apparatus and text-books, and the want of appre- 
ciation on the part of the general public, are great barriers 
in the way of progress. But these barriers must and will 
in time be removed, teachers will be better trained, more 
and better apparatus will be provided, better text-books 

(5) 



6 PREFACE 

will be written, and when all this comes to pass the public 
will soon learn to appreciate this line of educational effort. 

The object in preparing this little book has been to pre- 
sent in simple language some of the more important prin- 
ciples of agriculture, with the hope that as herein set 
forth they may serve to stimulate in the pupil a desire for 
further information on the subject. Details have been as 
far as possible avoided, for to attempt to load the pupil's 
mind with a mass of details would be to defeat at the start 
the primary object of the book. It must be borne in mind 
that within the limits of an ordinary volume it is impossi- 
ble to present more than a very brief outline of the first 
principles of agriculture. Many topics must be omitted 
entirely and others touched upon very briefly. It is hoped, 
however, that these first principles may provide the stu- 
dent with a ground-work upon which to build a more per- 
fect knowledge of agriculture. 

Teachers should, whenever possible, supplement and 
illustrate the text by examples drawn from their own 
observations and experience, and should encourage pupils 
to observe and investigate for themselves. 

For revising my manuscript and for many valuable sug- 
gestions, my thanks are due Dr. J. M. McBryde, of the 
Virginia Polytechnic Institute; Prof. T. C. Karns, of Ten- 
nessee; Mr. J. F. Jackson, of the Southern Planter; Prof. 
D. 0. Nourse, of the Virginia Polytechnic Institute; Mr. 
David Cloyd, of Dublin, Va.; Prof. C. E. Vawter, of the 
Miller Manual School; Dr. J. M. McBryde, Jr., of Hollins 
Institute, and Dr. F. D. Wilson, of the Virginia Polytechnic 
Institute. For the illustrations I am indebted to Dr. Chas. 
N. McBrdye, of the Virginia Polytechnic Institute. 

J. B. McB. 
Polytechnic Institute, Blacksburg, Va. 



COIN^TENTS 



PART I— Climate 



CHAPTER 


" 


PAGE 


I. 


Sunlight, - - - - - 


9 


II. 


Sunlight (Continued), 


14 


III. 


Rain, ------ 


18 


IV. 


The Atmosphere, _ - . . 


23- 


V. 


The Atmosphere (Continued), 
PART II— Plants 


28 


VI. 


Plants and Their Seed, 


33 


VII. 


Paris of a Plant, . - - - 


38 


VIII. 


Composition of Plants, 


45 


IX. 


Composition of Plants (Continued), - 


50 


X. 


The Food the Plant Takes from the Soil, 


55 


XL 


The Food the Plant Takes from the Air, 


60 


XII. 


How Plants Grow, - . . - 
PART III -Soils 


63 


XIII. 


How Soils are jNIade, - - - . 


67 


XIV. 


Classification of Soils, - - - 


72 


XV. 


Composition of Soils, - - - - 


78 


XVI. 


Composition of Soils (Contim-ed), 


83 


XVII. 


Water in Soils, - - - - - 


8S 


XVIII. 


Nitrogen in the Soil, - 


94 


XIX. 


How Soils Lose Water, - - - 


100 


XX. 


How Soils Lose Nitrogen, 


106 


XXI. 


How Soils Lose INIineral ISIatter, 


110 


XXII. 


Cultivation of Soils, - - 


117 


XXIII. 


Cultivation of Soils (Continued), 
PART IV— Maxukes 


122 


XXIV. 


Classification of Manures, 


128 


XXV. 


Commercial Fertilizers, 


133 


XXVI. 


Commercial Fertilizers (Continupd), - 


138 


XXVII. 


Use of Manures, . - - . 
(7) 


145 



8 


CONTENTS 




CHAPTER 


PART V— Farm Crops 


PAGK 


XXVIII. 


Seed Testing, . - . _ 


151 


XXIX. 


Classification of Crops : Cereal and Fod- 






der Crops, - . - _ 


157 


XXX. 


Fodder Crops and Pastures, 


164 


XXXI. 


Root and Tuber Crops : Miscellaneous 






Crops, 


172 


XXXII. 


Rotation of Crops, - - - - 
PART VI— Animal Production 


177 


XXXIII. 


Composition of Animals, - 


181 


XXXIV. 


Food, Work, and Growth of Animals, - 


186 


XXXV. 


Care of Animals, - - - - 


190 


XXXVI. 


Feeding of Animals, 


195 


XXXVII. 


Stock Food, . . - - 


198 


XXXVIII. 


Digestibility of Stock Foods, 


204 


XXXIX. 


Calculating Rations for Animals, 


?08 


XL. 


Selecting Stock Foods, 

PART VII— Miscellaneous Topics. 


214 


XLI. 


Birds, 


218 


XLII. 


Insectivorous Birds, _ . _ 


222 


XLIII. 


Seed-Eating Birds, . _ . 


228 


XLIV. 


Birds of Prey, - - . . 


233 


XLV. 


Forestry, - - - - 


238 


XLVI. 


Roads, - . - _ . 
Appendix 


243 




Tables, - - - - - 


251 




Index, - - - . - 


261 



Elements of Agriculture 



PART I.— Climate 



CHAPTER I.— Sunlight 

1. Sunlight the Source of all Life. — Sunlight, water 
and air, all three so important to our health and happi- 
ness, are equally necessary to the health and growth of 
plants. Children raised in the foul, dark slums of a 
city are apt to be sickly both in mind and body. The 
strongest alone survive, and they too often grow up as 
full of evil as their surroundings. Poor children! Their 
lives are spent between the dull brick walls of the city, 
with seldom a glimpse of the country with its glorious 
sunlight, its birds and its flowers. How can they grow 
up to be perfect men and women? Xo more can the 
little plant struggling along in some dark corner grow 
up to its full beauty and power. 

The light and heat which come to us from the sun in 
the form of sunshine are, as every child should know, 
the sources of all life on this earth; hence to sunshine 
agriculture owes its very existence. But little is yet 
known of this quickener of life. It is known that sun- 
shine produces both heat and light, and that the two 
may be separated, but much remains to be discovered in 



10 ELEMENTS OF AORICrLTURE 

regard to it; and men now unknown ma_y make their 
names immortal by telling tlie world more about it. 

2. Heat. — A stone thrown into a quiet pool of water 
produces waves^ which move rapidly from the place 
where the stone struck to the shore, where, striking 
against the grains of sand and soil ]^articles, they shake 
them about. When sunshine comes to the earth from 
the sun, it moves in waves just as perfect as those pro- 
duced in the water. But the waves of sunshine travel 
very much faster than the waves of water, and are so 
very small that they cannot 1)e seen. Nov;, these waves 
of sunshine coming from the sun strike against the 
surface of the earth and shake up its very small par- 
ticles, or molecules, as they should be called, much as 
the waves in the pool of water shake up the particles of 
soil on the shore. From the motion produced among its 
surface molecules the earth becomes warmed. If a crowd 
of children are all running about very fast and bumping 
into one another they soon become quite warm from 
the violent exercise. So with the small particles or 
molocules against which the sun's heat strikes; they 
become much excited, move about very rapidly, bump 
into one auother, and are thus warmed. 

3. Steam. — Wlieu a kettle of water is put over a fire 
to boil, the little heat Avavcs from the fire, which are 
like those froui the sun, first warm up the kettle. AYhen 
the kettle l^ecomes warm it transfers some of its heat 
to the water, and so motion begins among the molecules 
of water. This motion is slow at first, but as the heat 
waves from the fire continue to strike against the kettle, 
more aud more heat passes through to the water, and 



SUNLIGHT 11 

the motion of its molecules becomes faster. Soon the 
water begins to bubble and boil from the rapid motion 
of its molecules. Some of the surface molecules from 
their rapid motion are thrown off from the boiling water 
and float about iu the air in the form of a gas, which is 
called STEAM. 

4. Condensation. — If, in the steam from a boiling 
kettle, some cold object is held for a few moments drops 
of water collect on it. The heated molecules which make 
up the steam strike against the cold object and are 
cooled off, become quiet, and collect in drops of water. 
The steam is said to condense. When steam rises 
from boiling water into the air above, it cools off and 
gathers into fine drops of moisture, which make up the 
white steam to be seen rising from hot water. Xotice 
how dense and white the steam is on a cold day. 

5. Evaporation. — When heat waves from the sun 
strike against bodies of water, such as oceans, lakes and 
rivers, they cause rapid motion among the surface mole- 
cules of water; this motion is so strong at times that 
many of the water molecules are thrown off into the 
air above as they were from the kettle of boiling water. 
This change is called evaporation. But evaporation 
is not dependent on sunshine, though it takes place 
more rapidly under its influence. Air has the power of 
taking up water like a sponge, and like the sponge can 
hold only a certain amount. When air has taken up all 
the water it can hold, it is said to be saturated. Then 
evaporation ceases, but so long as the air is not satu- 
rated evaporation may go on. A bucket of water placed 
in a room protected from sunshine gradually evapo- 



12 ELEMENTS OF AGKICULTUEE 

rates, and so long as fresh air is admitted to the room 
so long will evaporation take jjlace. Wind causes rapid 
evaporation; sweeping across bodies of water, the air 
takes up water as it goes; it is somewhat like passing a 
dry sponge over a wet slate. Of course, the water 
warmed by the sun does not actually boil. Water 
evaporates when it is warmed, and the more it is warmed 
the more rapidly it evaporates. 

6. Mist, Clouds. — Most of us have noticed on a cool, 
frosty morning, when the sunshine strikes a pond or 
river, how it steams like a great boiling kettle of water. 
This is all the work of the little heat waves from the 
sun. They evaporate the surface water, which, rising 
into the cool air, is condensed into tiny drops of water, 
which form mist. Mist, then, is made up of very small 
drops of water. Mist, or fog, as it is sometimes called, 
rises high above the earth and gathers into what we call 

CLOUDS. 

7. Rain. — Clouds which we see floating about in the 
air are still warm from the sunshine which helped to 
form them. When they come in contact with a cold 
current of air, or a cold mountain top, they lose this 
heat and condense to drops of water, which being 
heavier than air fall as rain. The cold air or mountain 
top acts just as any cold body would if held in a cloud 
of steam. 

8. Hail, Snow. — Sometimes raindrops are caught in 
very cold currents of air. In these air currents they are 
held till they become balls of ice, in which form they 
fall as HAIL. When the air becomes sufficiently cold, 



SrXLlGHT 13 

the moisture in clouds is frozen into ice crystals^ which 
fall as SNOW. 

Questions 

1. To what does agriculture owe its existence? 2. What 
does sunshine bring to the earth? Can the two be sepa- 
rated? 3. How does sunshine travel to us from the sun? 

4. If you throw a stone into a quiet pool of water, what 
sort of motion is started on the surface of the water? 

5. Why can't we see waves of sunshine? 6. What happens 
when waves in a pond of water strike the shore? 7. What 
happens when waves of sunshine strike the earth's surface? 

8. When sunshine strikes bodies of water what happens? 

9. What is steam? 10. How are raindrops formed? 
11. What is snow? 



14 ELEMENTS OF ACJKICULTURE 



CHAPTER II.— Sunlight 

(Continued) 

9. Solids, Liquids, and Gases. — The changes which 
water goes through wlicn it evaporates to form clonds, 
and the freezing of clouds to hail or snow, show that 
water may exist in three different forms: first as a 
LIQUID, second as a gas, and third as a solid. Ever}^- 
thing we know is either a liquid, solid, or gas. Water 
may he easily changed from one form to another, but 
many substances arc very difficult to change. Iron, a 
solid, when heated very hot, melts to a liquid, and it 
may even be heated so hot tliat it becomes a gas. Air, 
under pressure, has been liquefied by intense cold, and 
other wonderful changes have been made. As a rule, 
heat causes substances to expand and melt, and if they 
are heated sufficiently high they expand still more and 
become gases. On the other hand, cold causes most sub- 
stances to contract and change from gases to liquids, 
and from liquids to solids. This expanding and con- 
tracting of bodies is made use of in the thermometer, 
which is a tube partly filled with mercury or alcohol. 
All of the air is carefully taken out of the tube, the 
mercury is then put in, and the tube sealed up. When 
the mercury is heated it expands and rises in the tube; 
when it cools off it contracts and falls. By this rising 
and falling in the tube we measure the intensity of heat 
or cold. 



SUNLIGHT 15 

10. Winds. — The heat waves from the sun perform 
an important duty in making winds. When the surface 
of the earth is warmed by the heat waves from the sun, 
it in turn warms up the air which is pressing against it. 
AYarm air rises, and cokl air, which is heavier, moves in 
to take its phice. Thus the air is constantly moving 
about, and the motion is called wind. The motion of 
the air helps to keep the earth from becoming too hot. 
Heated air rises and takes with it a quantity of heat 
from the earth; colder air comes in its place, and this 
in its turn is warmed up and carries off more heat. So 
this changing may go on until the eartli is cooled off. 
Notice the air near a stone or brick wall some hot day 
and see the waves of hot air rising. When a fire is built 
on a hearth it first heats the air, which, rising up the 
chimney, causes a draught. Winds are distributers of 
rain; moving over the country they carry with them 
clouds of moisture, which, when condensed, fall as rain. 
The winds from the oceans bring in to the land great 
quantities of rain clouds. 

11. Radiation. — During the summer, when the sun 
pours down great quantities of heat day after day, the 
earth becomes thoroughly warmed up. The land is 
warmed by the sunshine, and bodies of water are 
warmed even more thoroughly than the soil. Thus the 
earth is storing up heat in land and water for use at 
night and in the cold winter.. At night, when the sun 
has set and the supply of heat waves is temporarily shut 
off, the air would become very cold but for the heat the 
earth has stored during the day. The air pressing 
as^ainst the earth is warmed bv the stored heat, ami thus 



16 ELEMENTS OF A(iRICULTURE 

prevented from becoming intense!}' cold. When the 
earth warms iij) the air it is said to radiate its heat. 
Radiation means that a warm body is throwing oft heat. 
Tlie sun radiates heat; a hot stove or fire also radiates 
heat. The earth alwavs gives up its heat when colder 
air presses against its surface. Thus radiation may 
take place at any time, but it is usually greater at night, 
because the air is then colder. 

12. Light Waves. — The light waves wdiich come to 
us from the sun along with the heat waves also have 
their part to play in aiding the growth of plants and 
animals. Just what etfect they have we do not certainly 
know, but we do know that light is absolutely necessary 
to the growth of most plants. In far northern coun- 
tries, such as Norway and Siberia, farm crops make a 
more rapid growth than they do farther south. This 
rapid growth must be due to the abundance of light, for 
the days are never very warm, and often the ground is 
frozen a few feet below the surface. But during the 
season when plants grow the sun shines almost con- 
tiimously, the nights being only about an hour long, and 
the plants are thus abundantly supplied with sunshine. 

Questions 

1. What are the three forms in which all substances 
exist? 2. In which of these forms does water naturally 
exist? 3. When water is heated, what form does it take? 
4. When water is frozen, what form does it take? 5. How 
does heat affect iron? 6. How may air be changed into a 
liquid? 7. What effect has heat on most substances? 
8. What effect has cold on liquids and gases? 9. What is a 
thermometer? 10. How is a thermometer made? 11. What 



SUNLIGHT 17 

causes winds? 12. Tell how the heat waves from the sun 
set in motion air currents. 13. How do winds cool the 
surface of the earth? 14. How are rains distributed over 
the earth? 15. How is the earth kept warm at night? 
16. What is radiation? 17. Why do farm crops grow inore 
rapidly in northern than in southern countries? 



18 ELEMENTS OF AGEICULTURE 



CHAPTER III.— Eain 

13. Work of Rain. — We learned in the last chapter 
how rain clouds are formed; so now it is in order to 
consider the work done b}- the falling of these clonds as 
rain. Besides supplying water for our own use and for 
the needs of onr animals and crops, what does the rain 
do on a farm ? 

14. Erosion, Land Washing. — Did yon ever notice 
how muddy all the creeks and rivers are after a heavy 
rain, and did you ever stop to think where all this mud 
comes from and where it is going ? The gullies in the 
hillsides should tell you where the mud comes from; 
the sand bars and islands in the rivers and creeks tell 
you where part of it has gone. The next time it rains 
notice how the raindrops gather in low places into little 
streams of water, which carry away particles of soil and 
trash. As the rain becomes harder, more and more 
water gathers in these little streams, and more particles 
are moved along by them. These small particles of soil 
and pieces of gravel rushed along by the water grind 
each other into smaller fragments, loosen other par- 
ticles from the soil, and so a gully grows in the hillside. 
This making of gullies is called erosion. 

i 15. Sediment. — Xow, where does the water carry the 
soil and trash which it takes from the hillsides ? Follow 
one of these little streams of water and you will see 
that wliere it reaches level ground it moves more slowly 



RAIN 19 

and drops most of the soil and trash which it is carrying. 
But it is still nniddy from the fine particles which do 
not settle. These it takes to the nearest creek, which 
in turn takes them on to some river, which takes them 
to a sea or lake, and here they finally settle to a resting 
place in its bed. The particles of soil and trash carried 
hv the water are called sediment, and when this settles 
out from water it is said to he deposited. Thus muddy 
water is said to deposit sediment. 

Just try to think of the vast number of little streams 
of water at Avork each day carrying off soil from exposed 
hillsides. Much of this soil is deposited in the bottom 
lands of creeks and rivers, which are thus often made 
rich at the expense of the hills. But most of the small 
particles of soil which easily float find their way through 
the creeks and rivers to a sea or lake, and here they are 
deposited as bars of mud and sand. As the river is con- 
stantly bringing down more mud and sand, these bars 
grow and finally rise from the water to form new land. 

16. Leaching. — Eain water carries with it from the 
land other things besides mud and sand. Nearly every 
one knows that sea water is full of salt, but few stop to 
think where this salt comes from. It comes from the 
soil. Salt cannot be seen or tasted in ordinary soil, but 
it is there, along with many other substances that are 
also called salts, because they are like common salt. 
Besides salts there are many other substances in soils, 
some of which dissolve in water and som.e do not. Com- 
mon salt dissolves very easily in water, as do most of 
the other salts. When a rain falls, part of the water 
runs off on the surface of the soil, carryhig with it mud 



20 ELEMENTS OF AGRICULTURE 

and trash; but much of the rain soaks down into the 
soil and comes out again in springs and wells. The 
rain water in passing through the soil dissolves many 
substances which it takes with it when it comes from 
the soil. Mineral springs result when the water has 
dissolved much of the salts or other mineral matter in 
the soil. A water that has dissolved in it a large quan- 
tity of certain minerals is a hard water. A soft 
WATER is one almost free from any dissolved matter. 
When water dissolves substances and carries them from 
the soil it is said to leach the soil. The salts and 
other substances which water dissolves in its passage 
through the soil are caried by the water until it reaches 
some sea or lake. Here the salts remain; for when 
water evaporates it carries nothing with it, the salts and 
other impurities being left behind. Eain water, you 
know, is very pure and soft. So rivers are constantly 
pouring salts of various kinds into the sea, and as none 
comes out again the sea is becoming more salty every 
day. This change, however, is very slow; for seas and 
oceans, you must remember, are very large bodies of 
water, and it takes a vast quantity of salt to affect them. 
17. Rain as a Robber. — Judging by the way it be- 
haves to the soil, rain water must be considered a great 
robber, and when farmers are careless and give it a 
good chance, it will undoubtedly rob the soil of much 
that is valuable. If allowed it will also cut great gullies 
in exposed fields, wash away bridges and roads, and 
even take away crops from the fields. But where the 
rain does all this mischief it is usuallv the fault of the 



RAIN 21 

farmer, who has not properly protected his fields, crops, 
and roads. 

18. Evaporation as a Temperature Regulator. — An- 
other great work done by rain is to help to keep the 
earth from becoming too warm. The heat waves from 
the sun evaporate from the earth's surface great quan- 
tities of water to form clouds. The moisture which 
forms these clouds has been warmed by the heat waves, 
and, when it rises, carries with it much heat from the 
earth. Rising above the earth, the clouds come in con- 
tact with the colder upper air; here their heat is given 
up, or radiated, and they fall back as rain. The heat 
which they radiate passes through the thin upper air 
and is lost in outer space. 

EXPERIMENTS 

1. Take a glass tumbler nearly full of water and in it stir up some 
ordinary soil. As soon as you stop stirring notice how the soil par- 
ticles begin to settle, and observe which particles reach the bottom first. 
Notice also that some fine particles continue to float in the water for 
nours or even days. These are clay particles and only settle after a 
long time from still water. Add a little alum solution to this cloudy 
water and see what will happen. 

2. Evaporate clear spring water in a clean dish, and notice the 
deposit left in the dish. This deposit is made up of the salts which 
the spring water contains and which it has dissolved from the soil. 
Rain water if evaporated in a clean dish leaves almost no deposit. 

Questions 

1. How are rain clouds formed? 2. With what does the 
rain supply us? 3. How do rains affect exposed lands? 
4. How is a gully formed? 5. Where does the soil go 
which is washed from hillsides by the rains? 6. Why is the 



22 ELEMEIs^TS OF AGKICULTURE 

soil of creek and river bottoms usually richer -than the soil 
of hillsides? 7. When you stir up soil in water, which 
particles settle first after you stop stirring?- 8. Why does 
not the water become perfectly clear at once? 9. Where 
does the sea get its salt? 10. How are salts carried from 
the land to the sea? 11. Does rain water contain any salt? 
12. What is a hard water? 13. What is a soft water? 

PROBLEM 

An acre of soil one foot deep contains 43,560 cubic feet. 
The Mississippi River carries annually to the ocean about 
3,702,758,400 cubic feet of solid material. How many acres 
of soil one foot deep would this amount of material form? 



ATMOSPHERE 



23 



CHAPTER R^.— The Atmosphere 

19. Extent of the Atmosphere. — The earth is com- 
jDletely surrounded by a mixture of several gases, which 
is called the atmosphere, or air. The quantity of air 
becomes less and less as the distance from the earth's 
surface increases, until finally there is no more air, and 
what is called outer space begins. No one knows just 
how far the atmosphere extends above the earth, but it 
is variously estimated at from 200 to 500 miles. Per- 
sons climbing high mountains all notice how the quan- 
tity of air diminishes as they ascend, and how the cold 
increases. In the thin air of high mountain tops 
breathing l)ecomes difficult, and finally, owing to a lack 
of air and to the intense cold, a point is reached beyond 
which man cannot climb. It is probable that more than 
90 per cent of the atmosphere is included in the first 
fifteen miles above the earth. 

While the thin upper air will not furnish breath for 
man or beast, it serves the useful purpose of protecting 
the earth from the vast number of meteors — shooting 
stars as they are called — which are constantly falling 
into it. The number o£ meteors striking the upper air 
in twenty-fours hours has been estimated at two mil- 
lion. Meteors travel with enormous speed, and when 
they strike the upper air the friction produced is so 
great that it causes enough heat to burn them up. Most 
meteors are small bodies, and are burned up so far 



24 ELEMENTS OF AGRICULTURE 

above the earth that the little light they give off is not 
visible. Few meteors ever reach the earth. 

20. Composition of the Air. — Chemists tell iis that 
air is a mixture, consisting principally of two gases, 
nitrogen and oxygen, but containing in addition to 
these two main elements small quantities of several 
other gases, and even some liquids and solids. A gas 
called carbonic acid, or, more properly, carbon dioxide, 
another gas, ammonia, and water vapor arc three im- 
portant gases found in small quantities in the air. 
Water in the rain clouds and mist make up the liquid 
portion of the air, and dust particles and bacteria make 
up the solid portions. IN'ow, what are these various 
substances — nitrogen, oxygen, ammonia, etc. ? They 
are what chemists call elements and compounds. 

21. Elements. — Nitrogen and oxygen are elements. 
They are called elements because they cannot be 
divided into anything else. Iron is an element; it m.ay 
be divided into the finest possible pieces, but it is still 
iron. There is no known way of dividing iron into any- 
thing but iron, and this is true of nitrogen and oxygen. 
All substances that cannot be divided into anything 
else are called elements. There are something over 70 
elements known, but we shall be concerned in this book 
with not more than 16 or 17 of them. 

22. Compounds. — Two or more elements may unite 
with each other to form substances entirely different in 
appearance or behavior from either of the two elements 
themselves. Substances made up of two or more ele- 
ments are called compounds. Water is a compound, 
for it can be divided into two gases, oxygen and hydro- 



ATMOSPHERE 25 

gen, neither of which resembles water. All compounds 
can be divided into two or more elements. 

23. Mixtures. — Two or more elements, or compounds, 
may be mixed and still retain all their individual prop- 
erties. When this takes place the result is a mixture. 
Salt is mixed with flour to make bread, and in the mix- 
ture we cannot see any salt, but we can taste it and 
know from its taste that the salt is unchanged. 

Xow, air is a mixture of several elements and com- 
pounds. Let us see what these various substances are 
that go to make up air. 

24. Oxygen. — This element is a gas, and makes up 
nearly 23 per cent by weight of the air. It is the most 
abundant substance on earth, making up eight-ninths 
of the weight of water and about 50 per cent of the 
weight of sand. About one-third of the weight of soil 
and rocks is made up of oxygen, and all plants and ani- 
mals contain large quantities of the gas. Ox3^gen is a 
very active gas, always ready to combine with other 
substances, which, when the union takes place, are said 
to become oxidized. When substances combine with 
oxygen the action produces heat. Thus the carbon in 
coal when it burns unites with oxygen to form a gas 
called carbon dioxide, and gives off much heat. Com- 
bined with another gas called hydrogen,, oxygen forms 
a liquid which we know as water. Combined with iron, 
it forms a solid called iron ore. In plants and animals 
it occurs in combination as water, and also combined 
with some other substances to form solids. We breathe 
oxygen in the air, we drink oxygen in water, and we eat 



26 ELEMENTS OF AGRICULTURE 

oxygen in our food. We could not live for a moment 
without it. 

Oxygen alone is too active to support j)roperly the 
growth of plants and animals. In the air it is mixed 
with a slow, inactive sort of gas called nitrogen. 

25. Nitrogen. — In its hahits this element is very 
much the reverse of oxygen. It makes up nearly four- 
fifths of the volume of the air, or 77 per cent by weight, 
but does not readily combine with other substances. It 
is, however, very useful in agriculture, as no plant or 
animal can grow Avithout a supply of nitrogen. But a 
few plants have the power of obtaining nitrogen from 
the air, and animals obtain their nitrogen only from 
plants. Small quantities of oxj^gen and nitrogen are 
found in the air, combined with two other elements 
called hydrogen and carbon. 

26. Hydrog^en. — This element is a gas, and is the 
lightest of all known substances. All of the hydrogen 
found in the air is combined with other elements. Com- 
bined with oxygen it forms v\^ater; combined with 
nitrogen it forms ammonia. 

27. Carbon. — This element is a solid substance, and 
is well known in the shape of mineral coal, which is 
nearly all carbon. The diamond is also very nearly pure 
carbon, and so is the lead of an ordinary lead pencil. 
Carbon when heated in excess of air unites very readily 
with oxygen, forming the compound, carbon dioxide. 
Thus when coal is burned most of it disappears into 
the atmosphere as a gas, carbon dioxide, leaving behind 
only a few ashes. A large j^art of all plant and animal 
bodies is made up of carbon. 



ATMOSPHERE 27 

Questions 

1. About how far above the earth is the atmosphere 
believed to extend? 2. Where is the air densest? 3. How 
does the thin upper air protect the earth? 4. What is an 
element? 5. What is a compound? 6. What is a mixture? 
7. Is air an element, compound or mixture? 8. Name four 
gases found in the atmosphere. 9. Describe oxygen. 10. De- 
scribe nitrogen. 11. Describe hydrogen. 12. Name three 
well-known forms of carbon. 

PROBLEM 

Resting on each acre of land are about 4G,200 tons of air. 
If this amount of air contains 23 per cent by weight of 
oxygen, find the weight of oxygen gas resting on each acre. 



28 ELEMENTS OF AGRICULTURE 



CHAPTEE v.— The Atmosphere 
(Continued) 

28. Carbon Dioxide. — Though this gas makes up a 
relatively small proportion of the atmosphere, it is very 
important, as it supplies a large part of the food of all 
growing plants. The air ahout cities usually contains 
more of this gas than the air of the country. The many 
fires which are constantly kept going in cities give off 
great quantities of this gas. Ordinary air contains about 
.035 per cent by volume, or about 0.06 per cent by 
weight of carbon dioxide. This seems a very small 
amount, but when multiplied by the vast oceans of air 
it becomes a large sum. It is estimated that the air 
covering every acre of ground contains about 28 tons 
of carbon dioxide, which give lOJ tons of pure carbon. 
The supply of carbon dioxide in the air remains always 
about the same. The amount taken up by plants 
during their season of growth is replaced by the gas 
from fires, the breath of man and beast, and other 
sources. 

29. Ammonia. — This compound, often called harts- 
horn, is made up of nitrogen and hydrogen. It has a 
very powerful odor, but the air contains so little of it 
that it is not perceptible. This gas is very easily dis- 
solved in water, and rain washes it from the air and 
carries it to the soil, where it may become plant food. 



ATMOSPHEEE 29 

Though the amount in the air is very small, it is of 
some importance to plants. 

30. Moisture. — Water is found in the air as a gas 
known as water vapor. The amount of water vapor 
in the air is very variable, but warm air contains more 
than cold air. In cold air the water vapor condenses to 
form clouds or mist, in which form it is no longer a gas, 
but a liquid. Notice how drops of water collect on the 
outside of a glass of ice-cold water; the warm air which 
contains water vapor comes in contact with the cold sur- 
face of the glass, is cooled down, and the water vapor 
condenses to form drops of water. This is a good ex- 
ample of how dew is formed. At night when no heat 
comes from the sun the air becomes quite cool — cooler 
than the earth, which is warmed by the heat it has 
stored up during the day. Xow, when the air becomes 
cool enough, the water vapor it contains condenses to 
form drops of water, which are gently deposited on the 
surface of the earth and form dew. Dew is rain, formed 
near the earth's surface. When the air becomes suffi- 
ciently cold, the dew freezes and forms frost. 

Moisture in the air serves a useful purpose in helping 
to keep the earth warm. The heat waves which come 
to us from the sun move with wonderful rapidity, about 
186,000 miles in a second of time, and pass through the 
atmosphere as easily as water through a sieve. Striking 
the earth's surface, these heat waves warm it up; in 
other words, they start up other heat waves among the 
surface molecules of the earth. The heat waves thus 
started in the earth's surface move much more slowly 
than the heat waves from the sun, and they in time 



30 



ELEMENTS OF AGETCFLTURE 



start up other slow-in oving heat waves in the air press- 
ing against the eartli's surface. The heat waves started 
in the air tend to rise, but the moist, dense air near the 
earth's surface checks their upw^ard progress and holds 
them till the air l)ecomes thoroughly Avarmed by tlieir 
motion. Eising slowly through the dense air near the 
earth, the heat waves finally reach the thin upper air 
through which they pass very easily, and are soon lost 
in outer sj^ace. High mountain tops are surrounded 
by thin air, through which the heat waves from the 
earth pass so rapidly that it never becomes thoroughly 
warm, consequently they are always cold. The dense 
layer of air near the earth's surface acts like a heavy 
blanket or covering; the thin air of mountain tops is a 
very poor covering. 

Dew and frost seldom occur on cloudy nights, because 
the moisture in the clouds holds the heat waves from 
the earth, which keep the air warm and prevent the 
condensation of water vapor. Dust and smoke have 
much the same effect as clouds, and for this reason 
smoke is sometimes used to prevent frost. Wind also 
prevents frost, the air being kept in such rapid motion 
that little or no moisture is deposited. Moisture, dust, 
and smoke all tend to prevent radiation. In dry air 
radiation takes place rapidly, and consequently desert 
countries are nearly always cold at night, though warm 
in the day. 

31. Solid Substances in Air. — Dust particles may 
often be seen in the air, and especially is this true in 
dry w^eather, when they become so numerous as to be 
very disagreeable. Eain washes most of the dust from 



ATMOSPHEKE 



31 



the atmosphere, leaving the air fresh, clear, and cool. 
Along with the dust particles, and often carried by 
them, are many small bodies called bacteria. They 
are living bodies, but such small ones that they can be 
seen only by means of a good microscope. Some bac- 
teria cause disease in plants and animals, but others are 
A^ery beneficial to both, as you will learn later on. Xo- ■ 
tice the mold which forms on starch paste when it is 
left open to the air. This mold is caused by bacteria, 
which feed on the paste. If some substance poisonous 
to bacteria be mixed with paste no mold will form, and 
the paste keeps till it dries up. Oil of wintergreen is 
poisonous to certain bacteria, and is much used for pre- 
serving starch paste. 

32. Meteorology. — Wind, rain, and sunshine do not 
€ome and go by chance; their movements are regulated 
by laws as exact as those changing day to night and 
night back to day again. By studying these laws we 
may learn when to expect a change of weather. Scat- 
tered over our country are many weather bureaus, where 
men employed by the government are constantly watch- 
ing and recording the changes and movements of sun- 
shine, wind and rain, which changes go to make up 
what we call weather. It is very true that man cannot 
control the coming and going of sunshine, wind, and 
rain, but the successful farmer knows how to regulate 
his farming to suit the weather, and is always prepared 
to meet the changes which are constantly occurring. 
Some knowledge of meteorology — the science of the 
weather — is necessary in successful farming. This 
knowledge usually comes from years of experience and 



32 ELEMENTS OF AGRICULTURE 

observation on the part of the farmer, but now the 
weather bureaus supply, for the asking, information 
which has been collected as the result of years of 
patient labor. Each farmer should, however, keep a 
record for his own farm or locality, and if the work be 
done carefully and systematically, it will prove of value 
not only to him, but to his community and to his chil- 
dren after him. 

Questions 

1. Why is carbon dioxide important to growing plants? 
2. Why is there usually more carbon dioxide in the air of 
cities than in the air of the country? 3. What is ammonia? 
4. What is water vapor? 5. Which contains the more water 
vapor, warm or cold air? 6. When the water vapor in the 
air condenses on the surface of the earth, what is it called? 
7. How is frost formed? 8. How does dense, moist air behave 
towards the heat waves from the earth? 9. Why are the 
tops of high mountains colder than the country below? 
10. What do the dust particles in the air often carry with 
them? 11. What is meteorology? 



PLATs'TS AND THEIK SEED 33 



PART II.— Pl.vnts 



CHAPTER YI.— Plants and Their Seed 

33. Annuals, Biennials, and Perennials. — Most of the 
plants cultivated on the farm are grown from seed, a 
few grow from cuttings, and a few from roots, but the 
more important farm crops all grow from seed. Plants 
are often divided into three groups — annuals, biennials, 
and perennials. These words refer to the length of the 
plant's life. Annuals are plants living about one year; 
BIENNIALS, plants living about two years; and peren- 
nials, plants which live on year after year for an in- 
definite period. Annuals grow rapidly to their full 
size, produce a crop of seed, and die all in about one 
year's time. Biennials often reach their full size in one 
year, but do not produce seed till the second year. Af- 
ter producing a crop of seed they also die. These two 
classes of plants produce only one crop of seed. Peren- 
nials have no fixed lifetime — some such as oak trees live 
to be hundreds of years old, others live only a few 
3^ears. Most perennials produce seed each year; others 
only at longer intervals. 

34. Seed. — Most farm crops grow from seed; corn, 
oats, wheat; cotton, rice, arid tobacco all come from 
the planting of seed. Each crop produces but one kind 
of seed, and this seed when planted in turn produces 

3 



34: ELEMENTS OF AGRICULTURE 

again the crop. There is never a mistake — corn comes 
from corn seed and wheat from wheat seed with abso- 
lute certainty. 

A seed is the egg from which a phmt is hatched. An 
ordinary seed may well be compared to an egg. It con- 
sists usually of an outer shell protecting the soft inner 
portion, which is really the young plant folded up. A 
sitting hen warms her eggs w^ith the heat of her body 
till the necessary changes have taken place in the egg, 
then the chick begins to stir, and soon bursting the shell 
comes into the world a living animal. The apparently 
lifeless egg, when warmed by the hen, is changed into 
a living chicken. The equally dead-looking seed, when 
warmed in the soil by the sun's heat waves, bursts its 
shell and becomes a living plant. Most plants drop 
their seeds late in the fall, when a comparatively small 
number of heat waves come to the earth from the sun, 
and the earth is in. consequence cool. The seed lies on 
the surface of the ground all winter, the soft little plant 
folded up within being protected from the cold and wet 
by the hard outer shell. In the spring, when the heat 
waves begin to strike with more and more force on the 
earth's surface, the plant folded up in the seed begins 
to feel their effect, and soon bursts its shell and begins 
its life as a young plant. The warmth of the hen's 
body seems all that is necessary to hatch the egg, but 
other things besides heat are necessary to batch out a 
seed. Seeds may be kept in a warm, dry place for years, 
and yet never sprout ; but so soon as they are moistened 
they will, if alive, begin to sprout and grow. Water, 
then, as w^ell as heat, is necessary for the sprouting of 



PLANTS AND TIIEIK SEED 



35 



seeds. A seed planted deep in the soil will not grow, no 
matter if siip])lied with water and heat; but on or near 
the surface it spronts. Air, then, must also he neces- 
sary for the sprouting of seeds. By means of a few sim- 
ple experiments, described at the end of this chapter, 
any one may prove for his own satis- 
faction that water, heat, and air are 
necessary to sprouting seeds. 

A seed contains not only the 
young plant or embryo, Imt a 
sufficient store of food to nourish 
it until it can take its food from 
the soil. Take a fresh bean and 
notice how it is divided into two 
equal parts, joined at one end by a 
small stem. These two parts are 
called the seed leaves, and con- 
tain a store of food sufficient to 
nourish the growing plant until it 
can feed itself through its roots. 
Fig. 1 shows a young bean plant re- 
cently sprouted; c c are the seed 
leaves, and as the plant grows larger 
thev grow smaller till thev are finally 

" ^ ^ ./ YiG. 1— Bean seed re 

used up and only a wilted shell ^<^- X'l ^TT^ol^Sl 
mains, which soon falls off from t^-.^-^fo^iginardSw* 

,1 , ing from photograph.) 

the stem. • & t & i 

All seeds are j^rovided with a store of food for the 
use of the young plant, for young j^lants, like young 
animals, are not able to take care of themselves just at 
first. 




36 



ELEMENTS OF AGRICULTUEE 



The nourishment for the young plant is not alwaj^s 
stored in the seed leaves as it is in the bean, but often 
surrounds the 3'oung plant, as in the corn seed, as 
shown in Fig. 2. 




Fig. 2. — Grain of corn showing stages of germination: A, section of 
ripe seed enlarged ; /, seed-food, the portion that nourishes the young 
plant ; [/, germ of seed. B, showing seed just sprouted ; C, showing sprout- 
ing further advanced. I), showing sprouting still further advanced; 
young plant just showing above ground. (Original drawing from photo- 
graphs.) 



EXPERIMENT 



Fill an ordinary deep plate ivith sand or common soil, and moisten 
it tkoroughhj with water. Then cut apiece of flannel cloth just large 
enough to fit in the plate, and moisten thoroughly. Cover the soil 
with the damp flannel cloth, and over it scatter the seeds to he tested. 
Cover with another piece of damp cloth. Finally cover the ivhole 
with another plate, and set away in a. warm place, where the tempera- 
ture is about 80°. Fig. 3 shows a cut of this arrangement. Keep 
the flannel and soil damp hut not wet; if too much water is added, 
the seeds will rot. If the cloths are kept dry, the seeds will not sprout 



PLANTS AN'D THEIR SEED 



37 



at ally nor will they sprout if the temperature is kept below 40° or 
above 116°. If some of these same seeds be 2jlanted deep below the 
surface of the soil, afoot or more, they will never come up, but on the 




Fig. 3.— Simple apparatus for germinating seed: A, closed; B, open 
(From Yearbook, U. S. Dept. Agr., 1895, page 181.) 

surface Ihey sprout readily. From experiments such as this we learn 
that seeds must be supplied with certain quantities of heat, water, and 
air before they can sprout. 

Questions 

1. What is an annual? 2. What is a biennial? 3. What 
is a perennial? 4. How many crops of seed does a biennial 
plant produce? 5. How often do most perennials produce 
seed? 6. How is a hen's egg changed to a chicken? 7. How 
does heat affect most seeds? 8. What is necessary besides 
heat to sprout seeds? 

PROBLEM 

Make a list of all the plants you know in your neighbor- 
hood, and divide them into annuals, biennials and per- 
ennials. 



38 ELEMENTS OF AGRICULTUEE 



CHAPTEE YII.— Parts of a Plant 

35. Organs of Reproduction. — Many plants, as yon 
know, prodnce flowers, frnit, and seed; but these parts, 
or organs, as they are called, have nothing to do with 
feeding the plants which produce them. From the 
flowers come the fruit and seeds; the seeds produce 
other plants like the ones producing them ; hence, the 
flower, fruit, and seed are called the organs of repro- 
duction, because they reproduce other plants. 

36. Organs of Vegetation. — Most plants which grow 
on the farm have three distinct parts, two of which, the 
stem and leaves, are above ground and may be readily 
seen. The third part of the plant — ^^its roots — is buried 
beneath the surface of the soil, and can only be seen 
by digging down in the earth or by pulling the plant 
up. These three parts, or organs, are necessary to the 
health and growth of a plant. Cut off a plant's roots 
and it soon withers and dies. Cut off all its leaves and 
its growth is checked, and often the plant is killed. Cut 
away the stem and the leaves soon die ; the roots, how- 
ever^ if left in the ground, may put forth a new stem. 
Each of these three organs has its work to do in feed- 
ing the growing plant. They are called organs of 
vegetation. 

When the young plant bursts its shell and begins to 
grow, one part, the root, grows down into the earth; the 
other, the stem, grows in the opposite direction, towards 
the light. Fig. 2, page 36, shows how a grain of corn 



PARTS OF A PLANT 



39 



sprouts. The plant never makes a mistake in starting 
to grow; the roots always go into the soil and the stem 
and leaves to the light and air above. Why they do this 
we do not know, but we do know that the roots keep on 
growing into the soil, spreading out in search of food 
and water and taking a firm hold to 
support the stem and leaves above. At 
first, as you have been told, the food 
stored up in the seed feeds the young 
plant. Later on, when tlie plant be- 
comes stronger, it feeds itself through 
the roots and leaves. 

37. Roots. — We all recognize the 
gTeat variety of leaves produced by 
different kinds of plants, but the roots 
buried beneath the ground are less 
familiar, and while not nearly so varied 
in appearance as the leaves, are of many 
kinds and shapes. Many plants are pro- 
vided with one large main root, which 
goes deep into the soil. This root is 
called the taproot, and its branches 
are called lateral roots. Fig. 4 shows 
the taproot of a salsify plant. When 
the taproot is enlarged, as in the salsify 
and turnip, it is called a fleshy root. 

Instead of one main root, many plants have a number 
of roots of equal size. Fig. 5 shows the roots of a corn 
plant. Such roots are known as clustered or crown 
roots. When they are enlarged, as in the sweet potato. 
Fig. 6, they are called tuberous. Lateral^, or side 




Fig. 4,— Tap 
root of salsify 
fleshy root. (Ori 
ginal drawing 



from photo 
graph.) 



40 



ELEMENTS OF AGRICULTTTRE 



roots, and the j^ounger portions of main roots are cov- 
ered with fine thread-like branches that are called root 
HAIRS. These little roots are so small and delicate that 
they are difficult to find. But they may be seen by 
sprouting radish seed as described in experiment on 




Fig. 5.— Roots of a young 
corn plant; clustered or 
crown roots. (Original 
drawing from pliotograph.) 



Fig. G.— Tuberous roots of the sweet 
potato. (Original drawing from photo- 
graph.) 



page 36. Fig. 7A shows a young radish plant sprouted 
in this way; the root hairs show like fine threads. Fig. 
7B shows a young radish plant. pulled from the soil. 
Here the root hairs are covered by particles of soil, and 
if they are washed off the root hairs are destroyed. The 
root hairs are delicate tubes through which the plant 
draws much of its food and water. Fig. 8 shows the 



PARTS OF A PLANT 



41 



root hairs of an oat plant highly magnified. AYater 
easily passes through the walls of the root hairs, and 
from them passes on into the main roots, and finally 
into the plant stem. Each root liair 
is like a miniature well;, through 
which water rises into the main 
roots of the plant. When a grow- 
ing plant is taken from the soil 






Fig. 7.— Y oung radish 
plant: ^4, young plant sprout- 
ed as described in experi- 
ment, p. 3*5; i^, young plant 
pulled from the soil. (Origi- 
nal drawings from photo- 
graphs.) 



Fig. 8.— Root hairs 
of oat plant magni- 
fied 80 times; 
shows small soil 
particles being dis- 
solved by sap of 
the roots. (From 
Sachre's Exp. Phys. 
d. Pflarzen.) 



and replanted it nearly always wilts, taking several 
days to revive. It wilts because many of its root hairs 
are destroyed, and consequently its water supply is les- 
sened. In time new root hairs are formed and the plant 
revives. 

Eoots are useful to plants in two ways : First;, they 



4:2 ELEMEIS^TS OF AGEICULTtJRE 

supply the portion ol the plant growing above the 
ground with a lirm support. Second, they supply the 
plant with much of its food and water. 

The root hairs and smaller roots supply most of the 
food and water. The larger and stronger roots serve 
as carriers of food and support the growing plant. 

38. Steins. — Stems are more varied in appearance 
than roots. In large plants, such as trees and shrubs, 
the stem consists of a main upright portion called the 
TRUNK, which is provided with a number of branches 
called LIMBS, and they in turn are provided with 
branches called twigs. In most plants the stems are 
upright, and the general direction of the limbs is the 
same. But there are many plants 23rovided with hori- 
zontal stems growing along the surface of the soil; other 
plants are provided with drooping stems, which, after 
reaching a certain height, turn towards the earth again. 
Still others are provided with twining stems, and can 
only grow upward when provided with a support around 
which they grow. But whatever the shape and size of 
stems they all serve the same purpose. They bear the 
leaves, flowers, fruit, and seed of the plant, and they 
serve to distribute the food and water taken in by the 
roots and leaves. 

39. Leaves. — Leaves are more varied in size and 
shape than either the stems or roots, but most leaves 
have one striking point in common — namely, their color. 
With a few exceptions all living leaves are green, and 
a loss of this color only occurs through disease or death. 
The stems of young plants and the tender twigs of 
older plants are often as green as the leaves. The veins 



PAKTS OF A PLAA^T 



43 




of leaves are really a continuation of the stem. Fio-. 9 
shows veins in a leaf of beetle-weed. 

The green color of leaves is due to the presence of a 
substance called chlorophyll, or leaf-green, which 

is found in the leaves 
of all living plants that 
draw their food from 
the soil. This green 
coloring matter, chloro- 
phyll, has much to do 
with making the differ- 
ent compounds which 
go to make up the 
plant. In the autumn, 
when, the first frost 
falls, the leaves of 
plants lose their green color, taking many 
shades of red and brown. This change in 
color IS an indication that their life is over 
and that they are of no more use to the plant. 
AYhen the leaves die plant-growth ceases till a 
new crop is formed in the spring. 
EXPERIMENT 

Fill a small box with earth and in it2jlant a few seeds. After the 
plants hare begun to grow, cover them with a box having an opening 
to the light on one side only. After a time notice how the young 
plants grow towards the light. Remove the box and the plants change 
their direction and grow upwards. 



Fig. 9 —Veins in leaf 
of beetle-weed (Galax 
aphylla. L.) (Origi- 
nal drawing from 
nature.) 



Questions 



1. Into what three parts may a plant be divided? 
2. What are these parts called? 3. How many of these 



44: ELEMENTS OF AGI^ICULTURE 

parts can you see on a young plant? 4. Suppose the roots 
of a plant are cut off, what happens to the plant? 5. What 
are the flowers, fruit, and seed of a plant called? 6. Why 
are they so named? 7. When a young plant begins to grow, 
do all of its parts grow in the same direction? 8. Which 
part grows into the soil and which towards the light? 
9. What is the main root called? 10. What are its branches 
called? 11. What sort of roots have turnips? 12. What do 
we call roots like the sweet potato? 13. What are the stems 
of trees called? 14. Tell in what different ways the stems 
of plants grow. 15. What purpose do they serve? 16. In 
what ways are all leaves alike? 

PROBLEM 

Make a list of all the plants you know that have fleshy 
roots. Make a list of all the plants you know that have 
fibrous roots. 



COMPOSITIOIS' OF PLANTS 45 



CHAPTER VIII.— Composition of Plants 

40. Moisture. — When fresh, green grass is cut and 
dried in the sun it withers and dies, losing much of its 
original weight, and forms what is called hay. If dry 
hay is ground up fine and carefully dried in an oven or 
over a slow fire, it loses still more weight, and in time 
becomes j^erfectly dry. Plants dried by the sun and air 
are said to be air-drieD; and those dried by artificial 
heat are said to be chemically-dried. The reason 
plants lose weight when they are dried is because the 
moisture in the plants is driven off by the heat. To 
prove that this is true take any convenient dish, fill it 
with green plants, and heat it gently over a slow fire. 
When the dish becomes thoroughly warm hold some 
cool object, such as a cold, clean plate, over it and see 
how the moisture condenses on the surface. 

Fresh grass cut and dried in the sun loses three- 
fourths or more of its original weight, and when artifi- 
cially dried loses 80 per cent or more of its original 
weight. ^lost farm crops and trees are made up of from 
three-fourths to four-fifths water, and some plants con- 
tain even as much as 90 per cent water. Different 
plants, and different parts of the same plants, contain 
different amounts of water. The seeds appear to be 
perfectly dry, yet if they are ground up and heated they 
lose about one-tenth of their weight, which is moisture. 
Wood when first cut is said to be green, and though 
apparently dry, contains moisture, most of which is lost 



46 ELEMENTS OF AGIJICULTUEE 

when the wood becomes seasoned. Fresh young plants 
and the leaves of trees contain large amounts of water, 
75 per cent or more. The trunks of trees and the stems 
of older plants contain less moisture, usually less than 
50 per cent. Seeds contains less moisture than any 
other part of the plant, usually from 10 to 20 per cent. 

41. Dry Matter. — The part of the plant that remains 
after it is dried is called dry matter, and makes up, 
as we have seen, from one-tentli to one-fourth of the 
original weight of young plants. If dried plants are 
set on tire they burn, and only a little gray powder re- 
mains. This powder is called ash or mineral matter. 
When plants are burned, most of the dry matter disap- 
pears as smoke and gas, and this part is called the 
volatile or combL'STible matter. The amount of 
dry matter in different parts of the plant depends on 
the amount of water. The more moisture a plant con- 
tains the less dry matter, and the less water the more 
dry matter. 

42. Volatile Matter. — This is the portion of the plant 
that is changed into gas when the plant is burned, and 
is often called organic matter. Volatile matter is 
made up of a number of substances, Avhich we may 
divide into two groups, those containing nitrogen and 
those without nitrogen. There are a number of nitro- 
g»en-containing substances in plants, but we shall call 
them all by one name, protein. There are also a great 
many substances in the plant which contain no nitrogen, 
and those we shall call non-nitrogenous. The 
amounts of protein and non-nitrogenous substances 
vary in different plants, and in different parts of the 



COMPOSITION OF PLANTS 47 

same plant, to as great an extent as do the water and 
dry matter. Peas, beans, and clover contain more pro- 
tein than hay or straw. The seeds of beans and peas 
contain large quantities of protein, while the seeds of 
wheat and corn are made up principally of non-nitro- 
genons matters. 

43. Protein. — The nitrogen-containing substances 
of plants are all compounds which are made up of five 
elements — carbon, hydrogen, oxygen, nitrogen, and sul- 
phur — with sometimes the addition of very small quan- 
tities of another element called phosphorus. The first 
five of these elements are called the organic elements, 
because they make up such a large j^art of all organic 
matter. Their names are often abbreviated by writing 
simply the first letter of the name, thus: C for carbon, 
H for hydrogen, for ox3'gen, X for nitrogen, and S 
for sulphur. These five letters make a word, CHOXS, 
which may help one to remember how the nitrogenous 
matter of plants is made up. There are a number of 
different nitrogen compounds in most plants, but they 
are somewhat alike, and we may properly call them by 
one name, protein; just as we call the inhabitants of 
this country by one name, Americans. Albumen may be 
mentioned as one of the most valuable compounds that 
make up protein. The white of an egg is pure albumen, 
and is the best example of an albuminoid. 

Four of the organic elements, C, H, 0, and X, were 
described in Chapter III. The fifth element is sul- 
phur. 

44. Sulphur.-— This element is a solid substance, and 
is probably better known as brimstone. Sulphur is 



4:8 ELEMENTS OF AGRICULTURE 

widely distributed both in the vegetable and mineral 
kingdoms; all plants contain sulphur, and it occurs in 
large deposits in some parts of the earth. When eggs 
deca}' the sulphur in the protein unites with hydrogen 
and forms a gas called hydrogen sulphide, which has a 
very disagreeable odor. It is the formation of this gas 
that makes decaying eggs so disagreeable. 

45. Non-Nitrogenous Compounds. — In all plants 
there are a number of organic compounds that contain 
no nitrogen; such compounds are largely carbohy- 
drates. They are made up of carbon, hydrogen, and 
oxygen. The word carbohydrate means carbon com- 
bined with hydrogen and oxygen in the proportion to 
form water. The Greek word for water is liydor, so we 
speak of a substance combined with water as a 
HYDRATE. Here we have carbonhydrate or carbohy- 
drate. Starch, sugar, gum, and Vv^oody matter (cellu- 
lose) are all substances containing no nitrogen, and 
are made up of C, H, and 0. They are consequently 
carbohydrates. These four compounds make up a large 
part of all plants, and are found in varying quantities 
in different plants and different parts of the same plant. 
Sugar is found in the stem of sugar cane and sorghum, 
in the roots of sweet potatoes and beets, in the fruit of 
many plants, and small quantities are found in the seeds 
of most plants. Starch is found in the leaves of trees 
and the stems of young plants, in the roots of many 
plants, notably the sweet potato, and in the tubers of 
the Irish potato. The grains of many seeds contain 
quantities of starch; corn and wheat contain about 70 
per cent starch. Woody matter makes up the stem and 



COMPOSITION OF PLANTS 49 

bark of most plants. Besides tlie carbohydrates, fat or 
oil is found in plants, principalh' in the seeds: for in- 
stance, the castor-oil bean and cottonseed. 

EXPERIMENT 

Cut some fresh grass; weigh it and dry it in the sun. After it is 
dry weigh again and notice how much it has lost in weight. Now 
set it on fire and alloiv it to burn; weigh the ash. Calculate the per 
cent of both moisture and ash. 

Questions 

1. How is hay formed? 2. Why does hay weigh less than 
the grass from which it was cut? 3. What happens to hay 
when heated by fire? 4. Which contains the more moisture, 
a plant or its seed? 5. When moisture is dried out from a 
plant, what is the remainder called? 6. How is dry matter 
made up? 7. That part of a plant wliich disappears when 
the plant is burned is called what? 8. Into what two classes 
of substances can organic matter be divided? 9. Of what 
five elements is the nitrogenous matter of plants made up? 
10. What are these five elements called? 11. In what parts 
of the plant is protein usually found? 12. Give an example 
of a nitrogenous substance. 13. What are the best known 
non-nitrogenous substances found in plants? 14. What 
three elements make up carbohydrates? 

PROBLEMS 

1. If a certain hay contains 10 per cent of water, how 
many pounds of dry matter does a ton of such hay 
contain? 

2. Five hundred pounds of corn contains 350 pounds of 
starch, what is the per cent of starch? 

3. Five hundred pounds of oats contains 50 pounds of 
protein, calculate the per cent of protein. 

4 



50 ELEMENTS OF AGRICULTURE 



CHAPTEE IX. — CoMrosiTioN of Plants 
(Continued) 

46. Mineral Matters or Ash. — The ashes of plants are 
made up of a number of elements, which are combined 
into various compounds. Of the organic elements^ car- 
bon, oxygen, sulphur, and phosphorus are often found 
in the ashes of plants and sometimes nitrogen and 
hydrogen. Besides these elements the ash contains sili- 
con, chlorine, potassium, sodium, calcium, magnesium, 
iron, manganese, and minute quantities of several other 
elements. These elements are all combined in various 
ways with each other, none of them being found alone. 

47. Phosphorus. — This element, which is a solid sub- 
stance, has such a tendency to combine with oxygen that 
it is never found alone. Ordinary phosphorus must 
be kept under water to prevent its oxidizing. When 
phosphorus and oxygen unite, the union produces 
much heat, and this fact is taken advantage of in the 
manufacture of matches. Phosphorus is usually 
found combined with calcium and oxygen, in which 
form it is variously called calcium phosphate, phos- 
phate OF LIME, and BONE phosphate. I'his compound 
makes up a large part of the phosphate deposits of the 
world. Some form of phosphorus exists in the bodies 
of all plants and animals, and neither can grow without 
a supply of tliis element. The combined phosphorus in 



COMPOSITION OF PLAXTS 51 

soils and plants is usually spoken of as phosphoric 

ACID. 

48. Silicon. — This is a solid element^ which, com- 
bined with oxygen, makes sand, or quartz rock. Silicon 
never occurs free, but always combined with some other 
element, usually ox3'gen. Its compounds are called 
SILICATES. Combined with oxygen and other elements, 
notably potassium and sodium, it is found in the ashes 
of plants. 

49. Chlorine. — This element is a gas with a very dis- 
agreeable odor. It is very active, combining readily 
with many other elements. AVith sodium it forms salt, 
which is widely distributed over the earth. Compounds 
of chlorine with other elements are called chlorides, 
and they are found in the ashes of all plants. 

50. Potassium. — This is a solid element, which al- 
ways occurs in combination. It combines very readily 
with water, and forms what we know as lye or potash 
LYE. It also combines with chlorine, forming a com- 
pound resembling salt and known as potassium chlo- 
ride, commonly called muriate of potash. On the 
farm this compound is much used as a fertilizer. It 
combines with oxygen and carbon to form potassium 
carbonate. In some form it is found in the ashes of 
all plants. 

51. Sodium. — This is another solid element, which 
closely resembles potassium. It never occurs free, but 
always in combination. It forms compounds very simi- 
lar to those formed by potassium. With water it forms 
soda lye; with chlorine, salt; and with carbon and 
ox3^gen, sodium carbonate. It occurs in some form in 



52 ELEMENTS OF AGRICULTUEE 

the ashes of all plants. Wood ashes are often leached 
with water and the compounds of potassium and sodium 
which dissolve out^ form common lye, which is used to 
make soap. 

52. Calcium. — A solid element which never occurs in 
a free state, but always combined with some other ele- 
ment. With carbon and oxygen it forms a compound 
which is properly known as calcium carbonate. 
When this compound is heated very hot the carbon and 
part of the oxygen are driven off as carbon dioxide, and 
the calcium and part of the oxygen remain as quick 
LIME. Quick lime takes up water very rapidly and 
changes to slacked lime. Calcium in some form is 
found in the ashes of all plants. 

53. Magnesium. — This element is a metal of a light 
silver color. It unites with oxygen when heated, and 
the union gives a very brilliant light, known as magne- 
sium LIGHT. This light is used for making photographs 
at night, and the magnesium used for this purpose is 
called FLASHLIGHT POWDER. In the ashes of plants 
magnesium always occurs combined with some other ele- 
ment, and never as a metal. 

54. Iron. — This element is so well known that it 
scarcely needs a description. It is found in the ashes of 
all ])lants combined with some other element. TJie 
green coloring matter of plants contains iron. 

55. Manganese. — This is a metal that somewhat re- 
sembles iron. It is seldom found alone, but usually in 
combination with oxygen. Its compounds are similar 
to those of iron, and occur in small quantities in the 
^■;?hes of all plants. 



COMPOSITION OF PLANTS 



53 



Minute quantities of a number of other elements are 
found in the aslies of plants, but they are of no im- 
portance in agriculture, and need not be mentioned. 

The following diagram shows in a condensed form 
how the plant is built up : 



Plant -i 



' Moisture— 








i 


Hydrogen 




( Oxygen 




1 


Carbon 






Hydrogen 


i 




^ Nitrogenous Matter— Protein i 
(Albuminoids, Etc.) 


Oxygen 
Nitrogen 
Sulphur 
> (Phosphorus 




' Volatile < 






Matter 










• starch ' 










Sugar 


Carbon 






. Non-Nitroge- " 


Wood 


Hydrogen 




nous Matter 


Gum 








, on 


I Oxygen 


^ Dry 




Matter 








' Phosphorus 






Potassium 






Sodium 






Caleium 




^ Non-Volatile Matter or Ash ^ 


Iron 

Chlorine 

Silicon 

Manganese 

Magnesium 








• 




. Etc. 



54 ELEMENTS OF AGRICULTURE 

Questions 

1. In what form are elements found in plants? 2. Name 
twelve elements that make up most of the compounds in 
plant ashes. 3. Is phosphorus a liquid, solid or gas? 
4. What household article is made up in part of phos- 
phorus? 5. With what two elements is phosphorus usually- 
found combined, and what is the compound called? 

6. When silicon is combined with oxygen, what is formed? 

7. What are compounds containing chlorine called? 8. In 
what combinations is potassium found? 9. Describe an- 
other element that resembles potassium. 10. Describe cal- 
cium. 11. What is the compound of calcium with oxygen 
called? 



FOOD THE PLANT TAKES FROM THE SOIL 5o 



CHAPTER X.— The Food, the Plant Takes from 
THE Soil 

56. Water. — Most plants have only two sources from 
which to draw their food — namely, the soil and the air. 
From which of these sources do they draw their water ? 
Seed will not sprout in a perfectly dry soil. Deserts 
produce almost no plants, and in time of continued 
drought plants droop and finally die. It is evident that 
soil to sprout seed and grow plants must contain water; 
and from these facts we learn that plants draw their 
water supply from the soil. 

By rememhering that ahout 75 per cent of most 
young plants is moisture, we may form some idea of the 
vast amount of Avater taken from the soil hy many 
crops. Suppose an acre of ground produces a crop of 
green clover weighing 12,000 pounds, or 6 tons; about 
80 per cent of this is water, or 9,600 pounds or 4.8 tons. 
But this is not all the water an acre of clover requires 
while it is growing. You may drink a glass of water in 
the morning, hut in a few hours you are again thirsty 
and want more water. So with the clover; it is con- 
stantly drinking more water, and if not supplied the 
crop withers and in time dies. Xow, what becomes of 
all the water which plants drink up from the soil? 
They can hold only a certain amount, and as they are 
constantly drinking it in, some must be given off. If 
you will notice carefully the leaves of plants you will 



56 



ELEMETS'TS OF AGRICULTURE 



find that the upper side, which is the one turned towards 
the sun, is different from the lower side. By examining 
the lower side with a good magnifying glass you will 
notice many small openings in the leaf. These little 
month-like openings are called stomata, and have the 
power of onening or contracting. Fig. 10 shows some 

of these stomata. Through 
these openings the plant 
gives off water ajid takes in 
food from the air. Water 
thus given off by the plant 
is said to be exhaled. The 
plant takes in or absorbs 
water through its roots and 
exhales it through its 
leaves. This giving off of 
water through the leaves is 
also called transpiration, 
and may be compared to 




the 



off of water 



beings, which is called per- 



FiG. 10.— Stomata, or breathing fl-,T.QiTo-lT fVip qkin of human 

pores: .4, under side of leaf highly LnrOUgtl ine SKin 01 numan 
magnified; stomata shown at s; 
small hairs in leaf at /(. , 

B, section through stomata, ... rr^i i p 

highly magnified; .^ mouth of spiratlOll. the amOUllt 01 
stomata; a, air space in the leaf; 

f/, cells which as they expand or ^^.^^^pp wMch plants glve 

contract, open or close the sto- ^ ^ 

™^*^- off through their leaves, 

of course, varies, but most growing crops give off 
large quant^ies of water. On a dry, hot day grass 
plants have been known to exhale their own weight of 
water in twenty-four hours. Experiments conducted in 
Germany have shown that plants, for every pound of 
dry matter, require, during the time they are growing. 



FOOD THE PLANT TAKES FROSl THE SOIL 57 

about the following amounts of water: Oats, 376 pounds 
of water to one j^ound of dr}^ matter; wheat, 338 pounds 
of water to one pound of dry matter; red clover, 310 
pounds of water to one pound of dr}- matter. Take as 
an example the clover crop already mentioned, which 
Aveighed 12,000 pounds. As 80 per cent of this is 
Avater, we have 20 per cent dry matter, or 2,100 pounds. 
If one pound of dry matter requires 310 pounds of 
water, the 2,100 pounds must require 741,000 pounds 
of water, or 372 tons, or about 75,000 gallons. At this 
rate, to produce about one ton of clover hay more than 
300 tons of water are needed. 

The moisture in the atmosphere cannot be taken up 
by plants unless it first passes into the soil. 

A plant wilts because tlie leaves give off more water 
than the roots can supply. 

57. Nitrogen. — From the soil plants draw most of 
their supplies of nitrogen which is combined in the 
organic matter of t]ie soil. Xitrogen, if not the most 
important, is one of the most important of all the 
plant foods, and we shall have more to say about it when 
we come to write of .-oils. 

58. ' Mineral Matter. — The elements which make up 
the ashes of plants come, of course, from the soil, as 
they are not found in the atmosphere or largely in 
water. Although the amount of mineral matter con- 
tained in plants is very small, a proper suppl}^ is abso- 
lutely necessary. All soils contain the necessary ele- 
ments of plant food, but in many soils the supply is 
small, and in some soils the elements are so combined 
as to be unfit for plant food. When such is the case 



58 ELEMENTS OF AGKICULTUT^E 

they are said to be unavailable. For instance, nitrogen, 
which makes np four-fifths of the air, is a very im- 
portant plant food, but f)lants cannot take in free nitro- 
gen gas; it must first be combined with some other ele- 
ments, usually hydrogen and oxygen, before it can be- 
come plant food. Phosphorus is another valuable plant 
food, and when combined with certain quantities of 
calcium and oxygen, is readily taken up by plants, but 
alone or combined with larger quantities of calcium 
and oxygen it is not fit for plant food. 

Xitrogen, phosphorus, and potash are three im- 
portant foods that the plant takes up from the soil. A 
proper supply of these foods is often lacking in soils, so 
they, are added in the form of fertilizers. Iron is an- 
other important plant food. It is necessary for the for- 
mation of chlorophyll, the green coloring matter of 
plants, which utilizes the carbon dioxide of the air in 
the formation of starch. As all soils contain a great 
abundance of iron it is not necessary to add it as a fer- 
tilizer. Calcium is still another important plant food. 
Soils usually contain an abundant supply of this ele- 
ment, but it is sometimes found necessary to add it to 
the soil in the form of lime. These foods — nitrogen, 
phosphoric acid, potash, lime, and iron — are necessary 
to the growth of plants, and no crop can be grown with- 
out a proper supply of them. Nitrogen, phosphoric 
acid, potash, and lime are the four most often lacking 
in soils, and to make up any deficiency they are added 
in the form of fertilizers. 



FOOD THE PLANT TAKES FROM THE SOIL 59 

Questions 

1. From what two sources do plants draw their food? 

2. What will become of a seed in a perfectly dry soil? 

3. Where do plants get their water? 4. What per cent of 
growing plants is water? 5. What becomes of the excess 
of water taken by the plant? 6. How id this water given 
off? 7. What is this process called? 8. What are the 
openings in the leaves called? 9. Where does the mineral 
matter in plants come from? 10. From what source does a 
plant draw most of its nitrogen? 11. What supplies mineral 
matter for plants? 12. What is chlorophyll? 13. Why are 
fertilizers sometimes added to soils? 14. When are plant 
foods said to be unavailable? 15. When are plant foods 
said to be available? 

PROBLEM 

If a crop of oats contains 1,000 pounds of dry matter, 
about how many pounds of water has the crop used during 
the time it was growing? 



60 ELEMEJs^S OF AGRICULTURE 



CHAPTEE XI.— The Food the Plant Takes from 
THE Air 

59. Carbon.— Plants, as you have seen, get their water 
and mineral matter from the soil. Yon vronld then 
naturally inquire whether plants get their carbon from 
the soil. Carbon in some form is present in all soils, but 
plants do not use this carbon for food. It has been 
"proven by experiments that plants cannot grow unless 
their leaves are supplied with air containing carbon 
dioxide gas, which you remember makes up a small part 
of the atmosphere. Other experiments have shown that 
the leaves of plants absorb carbon dioxide from the 
air, take from the gas the carbon, and give off the 
oxygen. Men and animals reverse this process; they 
draw air into their lungs, where the oxygen of the air 
unites with the carbon in the bloody and is given off as 
carbon dioxide gas. Men and animals inhale oxygen 
and exhale carbon dioxide. Plants inhale carbon dioxide 
and give off oxygen. Animals cannot live in air con- 
taining much carbon dioxide. Plants cannot live with- 
out a supply of this gas. Leaves have often been called 
the lungs of plants, and in their manner of taking up 
food from the air they do resemble the lungs of animals. 
Breathing animals are constantly adding to the supply 
of carbon dioxide in the air; the leaves of plants are con- 
stantly absorbing it and returning to the air free oxy- 
gen. In this way plants aid in maintaining a balance^ 



FOOD THE TLAXT TAKES EKO:\I THE AIT^ 61 

which mean's that the amount of carbon dioxide in the 
air remains alwa3's about the same. 

The leaves of j^lants absorb carbon dioxide only in 
direct sunlight; on cloudy days the amount of gas ab- 
sorbed is small, and at night the plant not only does 
not absorb any gas, but actually gives off carbon 
dioxide just as animals do in breathing. The amount of 
carl)on dioxide tluis given off is, however, very small 
compared with wliat is taken up under the influence of 
light. 

60. Oxygen. — While the leaves of plants under the 
influence of sunlight take up carljon dioxide and give 
off oxygen, the roots of growing plants require a con- 
stant supply of free oxygen in order that they may 
grow. Seeds, you remember, require a supply of air 
before they will sprout, and it is the oxygen of the air 
that enables them to begin to grow. A seed supplied 
with only nitrogen gas will not sprout, no matter how 
perfect the other conditions. When plants are in bloom, 
and later on when they are forming seed, a constant 
supply of ox3^gen is necessary. Oxygen is then neces- 
sary for all growing plants from the beginning of their 
life to the end. Tlie air, of course, contains an abundant 
supply of oxygen for all the needs of the plant above 
ground — that is, for the buds, flowers, and leaves. The 
s]:)aces in soils, as you will presently learn, contain air, 
which supplies oxygen to the roots of plants. If for any 
reason the supply of air in the soil becomes exhausted 
the plant growth is checked. 

61. Ammonia Gas. — Air contains minute quantities 
of this gas, which supplies to plants a small part of 



62 ELEMENTS OF AGRICULTURE 

their nitrogen. This gas is not taken up through the 
leaves or stem, but through the roots. Eain water 
washes the ammonia from the air into the soil^ where 
it may be changed to a form suitable for plant food. 
The amount of nitrogen thus supplied to plants is_, how- 
pver, quite small. 

62. Nitrogen. — Some plants have the power of using 
the nitrogen of the air for food. There are, however, 
only a few varieties of plants that have this power, and 
of them we shall have more to say later on. 

Questions 

1. From what source do plants draw their supply of 
carbon? 2. How does carbon occur in the air? 3. In what 
form is carbon taken in by plants? 4. In breathing, what 
element is taken from the air by men and animals, and 
v/hat returned to it? 5. What element is taken from the 
air by the leaves of plants, and what returned? 6. Why 
are the leaves sometimes called the lungs of plants? 
7. Why is it necessary to loosen up the ground when 
planting seed? 8. What parts of plants take up oxygen? 
9. Does the air supply plants with any part of their 
nitrogen? 



HOW rLAATs> GROW 



63 



CHAPTER XII.— How Plants Grow 

63. Water Enters the Plant Through Its Roots.— We 

have learned in the last chapters what kind of food 
plants require and where they get it. Now the question 
arises, How does the plant take up its food from the 
soil and air? Through its roots and leaves, of course; 
but how? The roots have the power of sucking the 
moisture from the soil, through their root hairs, as de- 
scribed on page 30. Each little root hair is a minia- 
ture well from which the water rises into the plant. 

64. Mineral Matter Enters the Plant Through Its 
Roots.— Most of the mineral matter in the soil is in the 
form of solids, and, before it can enter the plant, must 
be dissolved. Under the head of leaching you were told 
how rain water dissolves various substances in the soil 
and carries them off to the ?3a. The water which the 
roots of ])hints take in contains dissolved in it much 
mineral matter, usually in the form of salts. In this 
way the plant can drink in its food dissolved in water. 
But not all of the mineral matter is taken up by the 
plant in this manner. All plants, you know, contain a 
liquid called sap. N"© doubt you have all seen it oozing 
out of a cut in some tree or plant. The sap which goes 
down into the roots can dissolve some minerals which 
water cannot, and it acts on the small fragments of 
mineral with which the root hairs come in contact. Fig. 
8, page 41, phows how the root hairs are covered by fine 
particles of mineral matter, which are being dissolved 



64 



ELEMENTS OF AGRICULTURE 



by the sap. Oxygen is also taken up by the roots of 
plants, and nitrogen compounds dissolved in water also 
enter the plant through its roots. 

65. Compounds are Manufactured in the Leaves.— 
Through their leaves plants draw from the air supplies 
of carbon dioxide ; through their roots they pump water 
and the salts it contains in solution; and from these 
compounds are made many substances that go to build 
up plants. Chief among these is starch, a substance 
with which every child is familiar, as it makes up a large 
part of many foods; wheat flour, corn meal, rice, and 
potatoes are mostly starch, every grain of which is 
manufactured in the leaves of the plant which grows 
them. The so-called starch factories of the world never 
make an ounce of starch. All they can do is to separate 
from the other substances with which it is mixed the 
starch that is actually made in the leaves of plants, 
and afterwards concentrated in the seed, root, or stem. 
The real starch factories are the green leaves of plants. 
Starch is made up of carbon, hydrogen, and ox3'gen — 6 
parts of carbon, 10 parts of hydrogen, and 5 parts of 
oxygen, or, as the chemist writes it, C^HioOj. Carbon 
dioxide the chemist writes COo, two parts of oxygen to 
one of carbon; and water he writes HO^, two parts of 
hydrogen to one of oxygen. It is evident that these two 
compounds contain all the elements necessary to form 
starch, and it is from them that the plant manufactures 
it. But how? We may mix water and carbon dioxide 
in varying proportions and under all sorts of conditions, 
but no starch results; we may mix six j^arts of carbon, 
ten parts of hydrogen, and five parts of oxygen, and 



HOW PLANTS GROW 65 

subject them to all sorts of conditions, but no starch 
results. Xo chemist, however skillful, has ever suc- 
ceeded in making starch. But the simplest little plant 
that grows knows the process, and every day in spring 
and summer, v,hen the sun shines, is busy producing this 
useful substance. The chlorophyll in the green leaves 
of plants is the starch manufacturer, the leaf is the fac- 
tory, and siinlight its power. When the waves of sun- 
light strike on the surface of green leaves the chloro- 
phyll is busy converting water and carbon dioxide into 
starch ; when the sunshine ceases the -chloropliyll stops 
work. But starch is not the only substance that is 
formed in plants. Sugar, oil, woody matter, protein, 
and various other compounds are likewise formed in 
the plant. Xo one knows exactly how these various 
compounds are formed in the plant, but it is very pro- 
bable that most of them are formed in the leaf under 
the influence of sunshine. The various carbohydrates 
are probably made from starch. The protein com- 
pounds, besides carbon, hydrogen and oxygen, contain 
nitrogen and sulphur, which elements are drawn from 
the soil. But as to just how they are made into the 
various compounds found in plants we do not ^t present 
know. 

66. Sap and Its Work. — The compounds formed in 
the leaves of plants are distributed by the sap to various 
parts of the plant as they are needed to build it up. As 
the plant grows older its various parts change in compo- 
sition. The stems of most young plants contain starch, 
sugar, and nitrogenous substances, which, as the plant 



QC) ELEME]VTS OF AGRICULTUEE 

grows older, are found concentrated in the seed, and 

the stem is then composed ahnost entirely of woody 
matter. 

EXFEIUMENTS 

Over a patch of green grass place a box or any other covering to 
exclude the sunlight. In a few days tlte grass begins to lose its colon 
and in time becomes xvhite. If exposed to the sun again it in time 
regains its color and continues to grow. 

Select a groiving leaf of bright green color, and tvithovt taking it 
from the plant cover a portion of the surface exposed to the light ivilh 
black j^aper. The paper may be pinned or sewed on and should fit 
close enough to cut off all the light. In time the portion of the leaj 
under the paper loses its color, turninq white. By cutting the paper 
info 2^ roper shapes, Jigures or letters may be formed on the leaf. 

Questions 

1. How do plants take up water from the soil? 2. How 
do plants take up their mineral food from the soil? 3. What 
is the juice found in the stems of plants called? 4. In 
what way does sap aid in the growth of a plant? 5. In what 
forto does the plant take its food from the air? 6. What 
well known substance is formed in the leaves of plants? 
7. Of what is starch formed? 8. How are the compounds 
formed in the leaves distributed? 9. Are all parts of plants 
of the same composition? 10. As the plant grows, in what 
respect does it change in composition? 11. Where is much 
of the plant food finally concentrated? 



HOW SOILS ARE MADE 67 



PART III— Soils 



CHAPTEE XIII.— How Soils are Made 

67. General Definition of Soils. — Many persons im- 
properly speak of soil as "dirt." Soil may be defined 
as the finely pulverized portions of the earth's surface 
in which plants may grow. Dirt means something un- 
clean or filthy, and the word should never be applied to 
soil. Soil, it is true, may become dirty, but fresh, pure 
soil is clean and destroys dirt and filth. 

Soil, as the word is ordinarily used, refers to only the 
first 6 to 13 inches of the earth's surface. The portion 
below this depth is called the sl'bsoil. There is usually 
a marked difference between the soil and subsoil. 

Land is made up of soils, rocks, stones, and beds of 
mineral ore. Eocks are the great beds of hard minerals 
which may often be seen projecting through the soil 
and sometimes making up whole mountain ranges. Beds 
of granite, marble, sandstone, and limestone are called 
rocks. 

Scattered through the soil are coarse, broken frag- 
ments of the rock masses called stones. Eocks and 
stones are made up almost exclusively of mineral mat- 
ter, and when they decay they form soils. It is hard to 
realize that the surfaces of rocks, which appear to be 
almost everlasting, are constantly being worn awaj to 



08 ele:mexts of agrtculture 

form soils^ but siu-li is Tiudoubtedly the case. If a soil is 
examined with a good magnifying glass it is found to ho 
made up of many small fragments of various shapes and 
sizes. The fragments resemble those which are formed 
Avhen a coarse stone is pulverized, and this is just what 
has liapponed. Coarser fragments of stone have been 
broken u]) l)y various agencies, and the small particles 
resulting have formed the soil. We may put it down 
as an accepted fact that the mineral matter of all soils 
has resulted from the brealving up of rocks and stones. 

68. Formation of Mineral Fragments in Soils. — Xow, 
how is it that these apparently indestructible rock 
masses have been so broken up as to form the great soil 
areas of the world? Soils are formed so slowly and 
quietly that we are not aware that such a work is going 
on about us, but soils are forming to-day just as they 
have been for thousands of years. The great soil-maker 
of the world is v/ater, and it has several different 
methods of uiaking soil. 

69. Mechanical Action of Water. — More soils are 
formed by the mechanical action of water than by any 
other agency, so we may best consider it first. 

The surfaces of all rocks, however smooth appa- 
rently, are filled with minute cracks. The surfaces of 
rocks long exposed to the weather are particularly full 
of irregularities; an apparently smooth rock, if exam- 
ined with a magnifying glass, will show many cracks and 
joints. Into these cracks and joints water penetrates, 
and if the temperature becomes low enough, the water 
freezes, the cracks become enlarged, and often pieces of 
rock break oil". Water always expands when freezing, 



HOW SOILS ARE MADE 69 

and the force exerted is tremendous. Strong glass bot- 
tles are burst by freezing water, and even iron vessels 
are torn to pieces. The surfaces of rocks exposed to 
the weather in temperate climates are gradnally being 
broken to pieces bv freezing water. This action of water 
is called mechanical to distinguish it from the chemical 
action, which we shall consider presently. The mechani- 
cal action of freezing water cannot, of course, form soils 
in warm countries. 

Eunning water also helps to form soils. Notice the 
stones in a creek or river bed. Tliey are all worn smooth 
by the action of the water. Once these stones were 
rou2:h and jagged in shape, but the running water has 
tumbled them about, grinding them together until all 
the rough edges are worn off. The small particles which 
result from the grinding are deposited by the' water and 
go to form soils. 

70. Chemical Action of Water. — Rain water dissolves 
many salts from the soil and washes the soil from ex- 
posed hillsides, but it compensates for this mischief by 
aiding in the formation of fresh soil. Eain water falling 
on the surface of rocks gradually dissolves away the 
portions soluble in water, and the insoluble parts crum- 
ble away and form soils. The great caves in limestone 
regions are the result of chemical action of water. Lime- 
stone is not very soluble in ordinary water, but water 
that has carbon dioxide gas dissolved in it — soda water 
is ordinary water containing carbon dioxide gas — dis- 
solves limestone much better than ordinary water. Eain 
water dissolves the carbon dioxide of the air, and also 
some that is formed from the organic matter in the soil, 



To ELEMENTS OF AGRICULTURE 

This water, containing carbon dioxide, enters the cracks 
and joints in limestone rocks, and, dissolving portions 
of them, gradually forms larger cracks and fissures 
which in time grow into caves. 

71. Other Soil Builders. — Plants also aid in the for- 
mation of soils. The fine root liairs of plants penetrate 
the cracks and crevices of rocks, and the root sap dis- 
solves away portions of the rocks' surfaces. The small 
plants which grow on the surface of rocks^, mosses and 
lichens, are especially active in forming soils. Their 
roots draw all their mineral food from the rock, and so 
gradually wear away the surface 

The ox3^gen and carbon dioxide of the air combine 
with many substances contained in rocks and, forming 
other compounds, help to wear away the original rock. 

The minute bacteria in the soil also aid in breaking 
up rocks, but their action is chiefly on the organic mat- 
ter which all soils contain. 

72. Org^anic Matter in Soils. — So far we have consid- 
ered only the mineral matter of soils, but it is by no 
means all of the soil. A soil made up exclusively of 
mineral fragments could no more grow crops than the 
original rocks from which the fragments came. Mixed 
with the mineral matter of soils are the decaying por- 
tions of plants and animals which make up its organic 
matter. As the organic matter of soil decays it forms a 
dark substance called humus, which gives to many soils 
their dark color. The organic matter of soils is of great 
importance, and we shall have more to say of it. 

Soils are then made up of two kinds of matter — or- 
ganic and inorganic. The organic matter results from 



HOW SOILS AEE MADE 71 

the decay of plants and animals; the mineral matter 
from the decay of rocks. 

EXPERIMENT 

When the weather is sufficiently cold, fill some glass bottle of con- 
venient size tuith water — an old ink bottle will answer. Stop up the 
mouth of the bottle and set it out to freeze. Bij the expansion of the 
water in freezing the bottle icill be brokrn. 

Questions 

1. What do we mean by the term soil? 2. Is it proper to 
speak of soil as dirt? Why? 3. To what part of the earth's 
surface does the word soil refer? 4. What is the difference 
between a rock and a stone? 5. What sort of fragments 
make up the greater part of all soils? 6. How are soils 
formed? 7. What substance is most active in making soils? 

8. Describe the mechanical action of water in forming soils. 

9. How does the chemical action of water help to form 
soils? 10. What other agents besides water form soils? 
11. From what sources do soils draw their supply of organic 
matter? 



72 



ELEMENTS OF AGRK'ULTUEE 



CHAPTER XIV.— Classification of Soils 



73. Transported Soils.— Soils seldom remain just 
where they are formed^ for the same forces that form 
them also move them about. Water, the chief soil 
^ P-. former, is also the chief soil transporter. Its 

action in moving soils has been already men- 
X tioned in Chapter III under erosion, and 
-)X \ ii^ay ^6 better understood by reference 
^'>/'T'^^? V to Fig. 11^ page 72. This figure is in- 
tended to represent a section of a 
rocky hill or mountain, and shows 
how the top has been worn away 
to form soil, which is moved 
into the .valley below. The 
i». „ . f dotted line ab 



I' 






"^ ^^' 









Fig. 1L— Erosion of hill or mountain side. The soil between the lines 
ab and a^b has been washed away, c shows coarse fragments; ,/', finer 
soil; s, stream. 

shows the original shape of the hilltop; a'b its present 
shape. The portion between ab and a'b has been grad- 
ually worn away by frost and rain, and the particles 
washed l)y rain to the more level land below. The coarse 
fragments are the first to stop, and as the ground be- 
comes more level the finer particles are deposited from 



CLASSIFICATION OF SOILS 73 

the running water and form the fertile soils of the river 
bottom. Many of the finest particles are washed into 
the river or creek, shown at s, and are carried off to be 
deposited probably hundreds of miles away. Whenever 
a river rises and floods the bottom lands, quantities of 
mud and sand are deposited on the flooded area. The 
mud and sand have come from hillsides, possibly many 
miles away, and in time they become part of the soil of 
the river bottom. Soils that have been moved from the 
place of formation are called transported soils, and 
are often a mixture of soils from many localities. 

Wind storms also move soils about to a limited extent. 
You have all noticed the great clouds of dust blown 
about by high winds ; and in very dry countries, such as 
the northern portions of Africa, the amount of soil 
moved is considerable. In our country, with the excep- 
tion of one or two Western States, the amount of soil 
moved by winds is of small consequence. 

In some parts of the world much soil has been moved, 
and is even now being moved, by glaciers, which are 
nothing more than rivers of ice. But glacial action is at 
present limited to a very small part of the inhabited 
world, and need not concern us. 

74. Soils in Place. — Soils that remain where they are 
formed are called soils in place. The soils that cover 
the slopes of hills and mountains for the most part 
belong to this class. Soils in place are seldom mixed 
with the soils of other localities, but result simply from 
the decay of the rocks about them. 

75. Soils Classified According to Composition. — Soils, 
whether transported or soils in place, vary in the way. 



74 ELEMENTS OF AOEICULTURE 

they are made up. Different kinds of rocks when they 
decay make different kinds of soil. For convenience 
the various kinds of soils have been given different 
names to indicate how they are made up. For instance, 
we have sandy soils, clay soils, muck, etc. 

1. Sandy soils include all soils that contain large 
amounts of sand. Such soils are no doubt familiar to 
most of us. 

2. Clay Soils include all those containing large 
amounts of clay. They may be easily recognized by 
their sticky character. Soils that are made up some- 
what equally of sand and clay are called loams. 

3. Sandy loams are soils made up principally of sand 
and clay, but containing considerably more sand than 
clay. 

4. Clay loams are also soils made up principally of 
sand and cla}', but containing more clay than sand. 

5. Soils that contain much decaying organic matter 
are variously called humus soils, woods mold, or 
garden soil. If this variety of soil also contains 
much moisture it is called peaty soil, swamp muck, 
etc. 

These five classes include all the soils commonly cul- 
tivated on the farm. There are other kinds of soil dif- 
ferent from any of these, but they are not the ordinary 
farm soils. 

76. Light and Heavy Soils. — Soils are often spoken of 
as light or heavy, but these words have no reference 
to the actual weight of the soil ; they refer simply to the 
way these soils behave when cultivated. A light soil is 
one that is easy to cultivate; such soils are porous, and 



I 



CLASSIFICATION OF SOILS 75 

the plow or other implement of cultivation moves 
through them, easily. A heavy soil is one that is more 
difficult to cultivate; it is stiff and offers more resist- 
ance to the plow or spade than a light soil. The so- 
called light soil, as a rule, contains much sand, and is 
by weight the heaviest of all soils. The heavy soils 
contain much clay, which is lighter than sand. Soils 
that contain much organic matter, peaty soils, are often 
light in both senses of the word. The following figures 
give approximately the weights of the different soils: 

Dry Sand. . . . 100 to 120 pounds per cubic foot. 

Loam 90 to 100 pounds per cubic foot. 

Clay 78 to 80 pounds per cubic foot. 

Peat, etc 30 to 50 pounds per cubic foot. 

77. Warm and Cold Soils. — According to their power 
of retaining the sun's heat, soils are called warm or 
COLD. The amount of heat absorbed varies greatly in 
different soils, and depends on several conditions, but 
may be to some extent regulated by careful cultivation. 
Plants for their proper development require a certain 
amount of heat in the soil. Seed will not sprout until 
the soil has become warmed to the required tempera- 
ture, and most farm crops attain their most perfect 
development only in warm soils. Controlling, as far as 
possible, the amount of heat absorbed by soils is then 
a matter of the greatest importance, and with this end 
in view it is well to consider some of the conditions 
which influence the amount of heat in soils. 

Water has the greatest influence on soil temperature; 
it is, in fact, the great temperature regulator of the 



76 



ELEMENTS OF AGRICULTUKE 



world. In the second chapter the influence of the 
evaporation of surface moisture on the earth's tempera- 
ture is discussed. This action may be compared to the 
evaporation of perspiration from the human body. The 
temperature of the human body is prevented from be- 
coming too high by the evaporation of moisture given 
off through the skin. So it is with the surface of the 
earth, which may be called the skin; when it becomes 
too warm moisture is given off and its evaporation cools 
the soil. In very wet soils moisture is continually 
evaporating, and in consequence such soils are usually 
cold. In dry soils, on the other hand, there is but little 
evaporation, and the soil through the sun's heat be- 
comes warm. As a rule, the dryer the soil the greater 
the amount of heat absorbed. When no moisture is 
found the soil is turned into a desert. 

The color of soils also influences the temperature. 
It is a well-known fact that dark clothes are warmer 
than white. So it is with soils — a dark soil is warmer 
than a light one. 

The composition of soils also has an effect on the 
amount of heat absorbed. As a rule, sandy soils are 
warmer than clay soils. 

The fineness of the soil particles has also a marked 
influence on its temperature. Coarse, rocky soils suffer 
from extremes of temperature. In fine, well-cultivated 
soils the temperature is almost uniform. 

Questions 

1. Soils that have been moved from their place of forma- 
tion are called what? 2. Soils that remain where they are 
formed are called what? 3. By what means are soils usually 



CLASSIFICATION OF SOILS 77 

transported? 4. Name the several classes into which soils 
may be divided? 5. What is a sandy soil? 6. What is a 
loam? 7. What is a clay soil? 8. What is meant by a light 
soil? 9. What is meant by a heavy soil? 10. What is 
meant by a warm soil? 11. Name a well known compound 
having a great influence on soil temperature? 12. How may 
the presence of water prevent a soil from becoming too 
warm? 

PROBLEMS 

1. If a soil weighs 78 pounds to the cubic foot, how many 
pounds in an acre of such soil one foot deep? 

2. If a soil weighs 90 pounds to the cubic foot and con- 
tains 75 per cent of sand, what is the weight of the sand 
in one acre of such soil one foot deep? 



78 ETEMENTS OF AGRICULTURE 



CHAPTEE XV.— Composition of Soils 

78. Water. — All fertile soils contai.ii water, though 
the amount varies greatly under varying conditions. 
The desert soil contains no water; the soil of the swamp 
contains an excess of water; and between these two ex- 
tremes are the great areas of cultivated soils. Water is 
a necessary part of all fertile soils. 

79. Organic Matter. — Besides water there are two 
kinds of matter making up soils — organic and inorganic. 
If a sample of soil be gently heated in an oven it loses 
in weight, and the loss is due to the evaporation of 
moisture. If the sample be burned at a dull, red heat 
it loses more in weight and changes color; this loss is 
due to the burning of organic matter, which passes off 
as gas and smoke just as it does when a plant is burned. 
See page 46. 

The organic matter of soils results from the decay of 
plants and animals. In cultivated fields the organic 
matter comes mainly from the stubble of harvested 
crops, the decay of dead weeds, and from the addition 
of stable manure. In wood land it results from the 
decay of dead leaves and the fallen branches and trunks 
of trees. As the organic matter of plants is made up of 
C, H, 0, N, S, so the organic matter in the soil must 
be made up of the same elements; and as organic mat- 
ter decays these elements form compounds which serve 
in time to build up other plants. Thus the organic 



COMPOSITION OF SOILS 79 

matter of plants may be used over and over again for 
plant food. 

The decay or rotting of organic matter in soils is due 
to the action of bacteria which inhabit the soil. These 
bacteria feed on the organic matter and cause decay. 
They are sensitive to heat and cold, and require a con- 
stant supply of fresh -air and water. That these state- 
ments are true is shown by the following well-known 
facts: Dead organic matter does not decay when frozen; 
thus frozen meat or vegetables may be kept for years 
and show no sign of decay. Dead organic matter may 
be dried and kept for a long time, but when moistened 
it decays. Dried or smoked meat is a good example of 
this. If sealed up from the air, organic matter keeps 
indefinitely. Canned goods are an example of this fact. 
The conditions under which the bacteria of decay act 
best are the same as those necessary for the sprouting 
of seed. They require heat, moisture, and air, and, as 
in the case of the seed, it is the oxygen of the air that is 
used. 

As we have already learned, the decay of the dead 
organic matter of the soil results in the formation of a 
substance called humus. Humus is a dark, almost black, 
product, which gives to garden soil its rich, dark color. 
It is a mixture of many different compounds, all of 
which are made up of the four elements — carbon, hydro- 
gen, oxygen, and nitrogen. Humus is of great import- 
ance in the soil, and we shall have more to say of it 
later on. 

80. Inorganic Matter. — The mineral matter Avhich 
makes up more than 90 per cent of most soils is a mix- 



80 



ELEMENTS OF AGRICULTURE 



ture of many different compounds. But there are two 
compounds which are common to all soils and which 
serve as a basis for their classification. These two 
compounds are sand and clay. 

81. Sand. — The element silicon, when combined with 
oxvgen, forms a hard compound, which we know as 
quartz rock. Quartz often forms small crystals, and in 
this form makes up a large part of many kinds of rocks, 
such as granite, sandstone, and some forms of limestone. 
When these rocks decay, the quartz particles being very 
hard and insoluble, remain behind and form what is 
known as sand. Besides quartz grains, sand contains 
fragments of other minerals, such as mica, particles of 
iron, and lime. Sand is seldom, if ever, made up ex- 
clusively of quartz. Silica, as quartz is called, makes 
up more than one-half of the dry land. It is found in 
many rocks, and makes up a large part of most soils. It 
is one of the most abundant :;ubstances on earth. Silica 
is almost insoluble in water; the sand of river and creek 
beds being practically unaffected by the running water. 
Water runs through sand easily, and after being wet the 
sand dries out quite rapidly. Sand has no tendency to 
become sticky, and though wet sand may stick to one's 
clothes or person, it is easily brushed off. Sand absorbs 
much of the sun's heat, as any one who has walked 
through warm sand with his bare feet can testify. Sand 
alone makes a poor soil for growing plants ; besides sup- 
plying little food itself, it holds little or no moisture 
and becomes very hot when exposed to the sun. 
• 82. Clay. — This substance in its properties is very 
different from sand;, though it is what chemists call a 



COMPOSITION OF SOILS 81 

silicate; that is, it contains the two elements which 
make sand, combined with another called aluminum. 
Aluminum is a light metal, much like silver in appear- 
ance, and much used for manufacturing small articles, 
such as combs, penholders, etc. The metal aluminum 
is made from clay. Aluminum, silicon, and oxygen make 

CLAY. 

Clay is a very soft substance, smooth and almost 
greasy to the touch. When dry it may be easily pul- 
verized, falling into a powder as fine as the finest flour. 
Pure clay, such as the fine grades of kaolin, has no 
sand or grit in it, and may be easily cut with a knife. 
When wet it becomes sticky like dough or putty, and 
may be moulded into any desired shape. Kaolin or pure 
clay is used to manufacture pottery and chinaware. 

In the soil, clay exists as a fine powder, and it is the 
clay particles that make soil sticky. Clay when once 
wet dries out slowly, hence clay soils retain water. As 
clay soils retain much water, which evaporates slowly^ 
they are, as a rule, cooler than sandy soils. Clay and 
sand have almost opposite effects in a soil. Clay in soils 
holds water, making the soil cool and moist. It is 
sticky, and serves to bind the particles of soil together. 
Sand, on the other hand, holds little moisture, and its 
■presence tends to make the soil warm and dry. Its 
particles are not sticky; hence sandy soils are loose and 
easy to work. 

EXPERIMENT 

Take some dean sand, wet it and mould it into any desired shape. 
Notice how soon it dries out and crumbles to pieces, Four water on, 
6 



82 ELEMENTS OF AGRICULTURE 

dry sand and notice how quickly it runs through, and how soon the 
surface of the sand dries out. Treat some ordinary clay in the same 
way and notice how differently it behaves. Mix the sand and clay 
in varying proportions and find the proportions of each required to 
furnish a mixture resembling the soils in your neighborhood. 

Questions 

1. Of what two kinds of matter besides *water are soils 
made up? 2. The organic matter in soils comes from what 
two sources? 3. What elements make up the organic mat- 
ter of soils? 4. What causes the decay of organic matter 
in soils, and what substance is produced by this decay? 

5. Why is it that frozen meat or vegetables keep so well? 

6. Why is it that smoked or dried meats keep? 7. Why is 
it that canned meats keep? 8. From what source is the 
mineral matter of soils derived? 9. Name the three prin- 
cipal constituents of soil. 10. Of what two elements is sand 
made up? 11. What are large rocks made up of these two 
elements called? 12. How is sand formed? 13. How does 
clay behave when wet? 14. How would figures moulded 
of wet sand behave when dry? 



COMPOSITION OP SOILS 83 



CHAPTEE XVI.— Composition of Soils 

(Coxtixued) 

83. Plant Food in Soils. — In the last chapter we con- 
sidered four substances — water, organic matter, sand, 
and clay, which make up so large a part of all soils. But 
while these substances make up a large part of all soils, 
they furnish the plant with but a small part of its 
mineral matter. Water and organic matter are both 
indispensable as plant foods, but sand is of almost no 
value, and pure clay is little better than sand. Sand 
and clay are not of much use as plant foods, but they 
serve as a sort of storehouse for the plant supply of food 
and water, and they also make up the soil in which the 
plant roots grow and develop. The clay particles in the 
soil hold water from which the plant may draw its sup- 
ply. They also hold certain valuable plant foods which 
they give up to growing plants. Sand prevents the soil 
from, becoming too wet and sticky, and also absorbs 
much heat from the sun. Mixed in with the sand, clay, 
and organic matter are small quantities of various min- 
eral compounds that make up the ashes of plants. Four 
mineral elements are absolutely necessary to the growth 
of plants; they are phosphorus, potassium, calcium, and 
iron. Many others are found in the ash of plants, but 
they do not seem to be as necessary as the four men- 
tioned. 

84. Phosphorus in Soils. — This element in some form 



84 ELEMENTS OF AGl^IOtTLTUKE 

of combination is found in all soils^ and comes from the 
decay of rocks which contain phosphorus compounds. 
It is in some instances found combined with lime, in 
which form it is called bone phosphate, making up, 
as it does, a large part of the bones of all animals. 
Often it is found combined with iron and aluminum, 
when it is called iron and aluminum phosphate. 
Most soils contain comparatively small quantities of 
phosphates, -.1 per cent being a fair supply; some rich 
soils may contain as much as .5 per cent, but this is 
unusual. Poor soils contain not more than .05 per 
cent. Besides the phosphates mixed with the finer 
soil particles, many of the coarse fragments in the 
soil contain a small quantity of phosphates, which, as 
the fragments decay, is added to the line soil. 

85. Potassium in Soils. — Compounds of this element 
are found in all soils, and come from the decay of rocks 
containing potash. The rocks which supply most of 
the potash of soils are called feldspars, and are 
found all over the earth. The potash in the soil is 
usually combined with silica to form compounds 
known as potassium silicates. 

Clay comes largely from the decay of the same rocks 
that supply potash to the soil, and as clay is also a 
silicate it is often united with potash to form double 
silicates. The amount of potash in different soils, 
of course, varies greatly; in some soils it reaches as 
high as 2 per cent; in poor soils it often falls below .1 
per cent. 

86. Calcium in Soils. — Compounds of this element 
make up a small part of all fertile soils, and are the 



COMPOSITION OF SOILS 85 

result of the decay of rocks containing some form of 
calcium. The compounds of calcium found in soils 
are popularly called lime. In regions where limestone 
rocks are abundant the soil is well supplied with lime; 
but where the soil has been formed by the decay of 
sucli rocks as sandstone but little lime will be found. 
The amount of lime in the soils is, of course, depend- 
ent on the amount of lime in the rocks from which 
they are formed, and for this reason the supply of lime 
in various soils is very different. As already men- 
tioned, the soils of limestone regions are well supplied, 
and are, as a rule, very fertile. The soils of the fa- 
mous bluegrass regions of Virginia, Tennessee, and 
Kentucky are formed from limestone rocks, and are 
noted for their fertility. Besides forming plant food, 
lime has a decided influence on the supply of nitrogen 
in the soils and also on their mechanical condition. 

The quantity of lime in soils varies greatly; in some 
rich limestone soils it. may reach 2 to 3 per cent, and 
in poor, sandy soils fall as low as .1 per cent. The 
calcium in soils is usually combined with carbon and 
oxygen to form a carbonate, or with phosphorus and 
oxygen to form phosphates. Sometimes it is com- 
bined with sulphur and oxygen to form a sulphate. 

87. Iron in Soils. — This element occurs abundantly 
in all soils, however poor. It is usually found com- 
bined with oxygen, forming an oxide, or with oxygen 
and water to form a hydrate; at times it is combined 
with phosphorus- and aluminum. Nearly all rocks con- 
tain iron, which becomes a part of the soil when the 
rocks decay. Iron gives to soils their various colors 



8Q ELEMENTS OF AGKICULTURE 

of red or yellow. The amount of iron in most culti- 
vated soils seldom falls below 1 per cent. 

88. Other Elements in Soils. — Sodium, magnesium, 
chlorine, aluminum, and a number of other elements 
besides those already mentioned are found in soils; 
but they are of little importance as plant foods, so need 
only be mentioned. 

89. Analyses of Soils. — To analyze a soil means to 
determine the various elements and compounds it con- 
tains. The following figures show the comparative 
composition of samples of rich and poor soils. These 
figures are from actual analyses, the rich loam being a 
sample of soil from a rich bluegrass region, and the 
poor sand a soil from a very poor region of country: 

Rich Loam. Poor Sand. 

Limestone Soil. Sandstone Soil. 

Organic matter 5 per cent. 2 per cent. 

Sand 75 per cent. 90 per cent. 

Clay 20 per cent. 8 per cent. 

With the sand and clay: 

Potash 0.5 per cent. 0.1 per cent. 

Phosphoric acid 0.2 per cent. 0.05 per cent. 

Lime 0.5 per cent. 0.05 per cent. 

Iron 2. per cent. 0.8 per cent. 

Questions 

1. How do sand and clay aid the growth of plants? 

2. Name four mineral elements necessary to plant growth. 

3. From what does the phosphorus in soil come? 4. With 
what other compounds is it usually combined? 5. Give 
some idea of the amount of phosphoric acid found in soils. 

6. From what rocks does the soil's supply of potash come? 

7. With what substance is the potash of soils usually com- 
bined? 8. What rocks form soils rich in lime? 9. Why do 



COMPOSITION OF SOILS 87 

sandstone soils contain little lime? 10. What is a general 
characteristic of limestone soils? 11. With what element 
is the calcium in soils usually combined? 

PROBLEMS 

i. A sandy soil weighs 110 pounds to the cubic foot, and 
contains 0.04 per cent of lime. Calculate the total weight 
of lime in an acre of such soil one foot deep. 

2. A rich loamy soil weighs 90 pounds to the cubic foot 
and contains 0.60 per cent of lime. Calculate the weight 
of lime in an acre of such soil one foot deep. 



88 ELEMENTS OF AGKICULTURE 



CHAPTER XVII.— Water in Soils. 

90. Importance of Water in Soils. — Water and 
nitrogen have both been mentioned as making up a part 
of all fertile soils, but so far we have devoted little space 
to them. These two plant foods are of so much impor- 
tance that they each require a separate chapter for their 
consideration, and we shall begin with water. In order 
that any soil m.ay grow plants a supply of water is 
absolutely necessary; therefore it is of the first im- 
portance. 

91. Film Moisture. — Soils are made up of a great 
number of particles of various shapes and sizes piled 
loosely together. A pile of broken rocks or stones may 
serve to illustrate on a large scale how soils are made 
up. The spaces between the soil particles are filled with 
air or water, as the case may be. In dry soils most of 
the spaces are filled w^ith air; but when the soil becomes 
wet the air is driven out, and they become filled with 
water, and at the same time each soil particle becomes 
surrounded with a film of water. Dip a marble in 
water and notice how it comes out wet all over; it is 
surrounded by a layer or film of water. When soil 
becomes thoroughly wet each soil particle is surrounded 
by a film of moisture, like the wet marble. The water 
filling the air spaces soon sinks deep into the soil 
and part of it drains ofi^, leaving in the upper soil only 
the moisture surrounding each particle of soil, or what 



WATEK IN SOILS 



89 



is called the film moisture. This does not drain of? 
and serves to keep the soil moist, supplying water for 
growing plants. The amount of water held as film 
moisture varies greatly in different soils. 

Pour water over a pile of broken stones or coarse 
■gravel. Each stone soon becomes surrounded by a film 
of water; then the pile will hold no more water, and if 
more is added it simply runs off. Exposed to the air 
or sun, the pile of stones soon dries out, and the 
moisture disappears, leaving the stones as dry as before 
they were wet. Xow, pour water on a lump or two of 
dry clay, of about the same weight as the stones, and 
notice how much more water it absorbs than the stones. 
After the clay becomes thoroughly wet, it may be 
exposed to the air and sun a long time before it dries 
out. The clay consists of a great number of small 
particles, each of which, . when wet, becomes covered 
with water; most of the air spaces between the particles 
are also filled, and in this way much water is taken- up. 
As only the outer particles are exposed to the air and 
sun the lump dries out slowly. The pile of stones, on 
the other hand, consists of a small number of coarse 
particles, and consequently holds less film moisture. 
The water quickly drains from the air spaces, leaving 
each particle exposed to the air, which quickly evapo- 
rates the film moisture. 

The Cornell Experiment Station has published two 
interesting drawings illustrating the amount of water 
held by different soils. This experiment was made by 
the Station Chemist, and is described as follows: 

" He put small marbles in a tumbler, as shown by 



90 



ELEMENTS OF AGRICULTURE 



Fig. 12, and the total amount of film moisture that the 
marbles would carry is represented in the tube placed 
beside the tumbler. The soil in the other 
tumbler (Fig. 13) is of the same weight as 
the marbles in Fig. 12, and it represents the 
marbles reduced to the fineness of common 
sand. Its capacit}^ for holding iilm moisture 
is represented by the water in the standing 
tube (Fig. 13). The weight of material is 
the same in each tumbler, and the reason 
why one holds three times more film moist- 
ure than the other is due to the increase of 
surface that comes by dividing a coarse lump 
into fine particles."* 

This experiment seems to prove conclu- 
sively that the power of a soil to hold water 
depends in a large measure upon the fine- 
ness of its particles 
92. Free Water.— 

When rain falls on the 

surface of the earth, 

part of it sinks into 

the soil unti^. it reaches 

some hard layer of 

earth or rock, through 




Mi 




Fig. 12— Film 



Fig. 13.— Film 
moisture held by 



moisture held by ...jiich it cannot paSS. f^^^^^' '''''''' '^^ 



marbles. (From 
Bulleiin No. 174, rpi 
Cornell Experi- ^ ^^^ 
ment Station.) 



to powder. 
1 (From Bulletin No. 

nas 174 Cornell Experi- 
p ment Station.) 

from 



water that 
drained down 
the soil above rests on this layer, and follows it until it 
comes out as a spring or well. Fig. 14 shows how 



''Cornell Experiment Station Bulletin, No. 174. 



WATER IX SOILS 



91 



springs and wells are formed. The water that follows 
this impervious layer is called free or ground water, 
to distinguish it from^ the film moisture surrounding 
each soil particle. It must not be supposed that the 
ground water flows in a regular stream along this 
impervious stratum, for it does not. It fills all the 
spaces in the soil h'ing directly above the stratum, and 
drains gradually towards the spring (Fig. 1-i). We 
have, then, as shown in the figure, first, a layer of soil 
containing only film moisture, then a layer of wet soil, 
containing free or ground water, and, finally, the 




Fig. 14.— Water table in soil, a h, surface of ground ; C, 
soil containing film moisture; D, soil containing free 
water; E, impervious stratum; .s; spring; E, stream; W, 
well . X z, line of water table. 

impervious layer. The digging of a well proves the 
truth of these statements; the well first passes through 
a comparatively dry soil which carries only film 
moisture. Finalh', the well reaches a layer of soil 
which is wet, and as it sinks into this layer it fills with 
water to the point where the wet soil begins. If carried 
deej^ enough, below this wet soil will be found a layer 
of hard clay or stone. There is usually a well marked 
line where the soil containing film moisture ends and 
the free water begins; the line xyz in Fig. 1^ shows 
where the change occurs, and it is called the water 



92 ELEMEA^TS OF AGRICULTURE . 

TABLE. The water table is the beginning of the free 
water in the soil. Below the water table the soil is like 
a great sponge filled with water, and it is from this 
supply of free water that the soil above draws its supply 
in dry weather. The bottom of wells must always go 
below the water table. As film inoisture evaporates 
from the surface soil, more rises from the free water 
below to take its place. Dip the end of a dry towel in 
water, and notice how the water rises through the towel 
towards the dry end; a dry sponge sucks up water in 
the same way and illustrates perfectly how film water 
rises towards the surface of the soil. Part of the free 
Avater drains from the soil at some spring or well, and 
the remainder rises to supply the film moisture in the 
soil above. The supply of water in soils is renewed 
from time to time by rain, and as more rain falls the 
water table rises; in very wet weather it may reach the 
surface of the ground, and when such is the case the 
soil is completely saturated with water. In dry weather 
as the w.ater drains from the soil, the water table sinks 
lower and lower, till finally it sinks so low that almost 
no film moisture reaches the soil above. Then a 
drought is at hand, and plants growing in the soil 
suffer for water. 

93. Deep and Shallow Soils. — When the impervious 
stratum is near the surface of the soil the water table 
is also near the surface, and consequently in rainy 
weather the soil becomes very wet; on the other hand, 
in dry weather the small quantity of film moisture in 
the soil evaporates quickly, and leaves the soil very dry. 
Such soils are said to be shallow. When the imper- 



WATKR IX SOILS 93 

vious stratum is far below the surface the soil is said 
to be deei3. 

Water, then, is found in the soil in two forms; in 
the soil near the surface it ordimirily exists as film 
moisture. In the lower soil it is found as free water, 
which, rising in the soil, forms the film 
moisture above. ^ ^ 

EXPERIMENT % ^ 

To illustrate hoiu free water rises in soil and becomes B I 
^Im moisture, the following simple experiment is useful: t xf 

Take an ordinanj glass tube of any convenient size § " 
and stop up one end with a plug of loosely fitting cotton. ^ %• 
Then fill the tube with dry soil. Dip the end with the ^g 
cotton 2^lug in water just deep enough to cover the end B.^ 
of the tube. Water rises through the dry soil until it is c = 
all thoroughly moistened. Fig. 15 illustrates this ex- Z.^ 
periment. ^ ° 



Questions 



1. When a marble is dipped into water what 5 
happens to it? 2. When water is poured on a i 

pile of stones with what does each stone become S 

surrounded? 3. When rain water soaks into g 

the soil with what is each little soil particle 
surrounded? 4. What is the moisture surrounding each 
soil particle called? 5. Which absorbs the more moisture, 
a pile of fine earth or a pile of stones, and which dries out 
the more rapidly? 6. When water which soaks through the 
soil reaches a hard layer of soil or rock through which it 
cannot pass what happens to it? 7. What is the water that 
fills the soil just above the impervious stratum called? 
8. The dividing line between the soil filled with free water 
and that containing film moisture is called what? 9. Why 
does the level of a water table change? 10. How deep does 
a well have to go in the soil before it reaches water? 
11. How does the free water supply film moisture to the 
soil above? 12. In wet weather how does the water table 
behave? . ., 



94 ELEMENTS OF AGRICULTURE 



CHAPTER XVIII.— Nitrogen in Soils 

94. Importance of Nitrogen in Soils. — We have 

already mentioned the fact that nitrogen is one of the 
most iniiDortant of all plant foods. It is important 
because no plant can grow without a supply of this 
element, and, furthermore, because the supply in the 
soil is easily exhausted through careless cultivation, 
and, when once exhausted, is with difficulty replaced. 
It- seems strange that plants should ever want for 
nitrogen when they are surrounded by air which is four- 
fifths nitrogen. But there are only a few kinds of 
plants that can make any use of the nitrogen of the 
air, and even for them the nitrogen must first enter the 
soil and there be changed into the proper compounds. 
All of the plant's nitrogen supply is taken in through 
its roots. 

95. Sources of the Soil's Supply of Nitrogen. — The 
soil's supply of nitrogen comes from three sources. 
First, and most important, is the nitrogen combined 
in the organic matter in the soil; second, the nitro- 
gen contained in the air which fills many of the spaces 
between the soil particles; third, the compounds of 
nitrogen, ammonia and nitrates, which are washed 
from the air by rain water. The amount of nitrogen 
brought to the soil by rain water is insignificant com- 
pared with the amount supplied by organic matter. 
The nitrogen held by the air in the soil is useful to 
only certain kinds of plants, and by far the most im- 



NITKOGEX IX SOILS 



95 



portant compounds of nitrogen are those contained in 
the organic matter. 

96. Nitrification. — All the nitrogen compounds of 
plants are, as stated l)efore, called by one name — 
protein. When plants decay in the soil the protein 
compounds are destroyed by the bacteria which feed 
on the organic matter. Most of the nitrogen of the 
protein compounds is finally changed by the processes 
of decay into other compounds of nitrogen, which are 
known as nitrates, and this change is called nitrifi- 
cation. 

All of the changes which the protein compounds 
undergo in being converted into nitrates are caused 
by bacteria, which work only under certain conditions. 
These conditions have already been stated on page 78, 
and they show that in temperate regions of the earth 
nitrification can only take place during the summer 
months. This is fortunate, for the nitrogen compounds 
formed by this process are very easily dissolved in 
water, and if not taken up by growing plants would be 
quickly washed from the soil by rain water and so lost. 
Xitrification can only take place in moist soils well 
supplied with air, and is most active when the tem- 
perature is between 95° 'and 100° F. Xitrification 
ceases when the temperature rises above 130° F. or 
falls below 53° F. The nitrates are easily dissolved in 
water, and in this condition pass into the roots of 
plants and are finally built up by the growing plant 
into fresh protein compounds. By this process of 
nitrification the same nitrogen is used over and over 
again. J3ut, of course^ there is always some loss of 



96 ELEMENTS OF AGRICULTURE 

nitrogen. During the process of decay some of the 
nitrogen escapes into the air in the form of ammonia; 
the smell of ammonia may often be noticed rising from 
decaying organic matter. Then some of the nitrates 
are washed from the soil by rain water. In some way 
this loss must be made good, else the store of nitro- 
gen in time becomes exhausted. The nitrogen com- 
pounds washed from the air are not in sufficient 
quantity to make good this loss^, the minerals in the 
soil can supply no nitrogen, and the only remaining 
source is the free nitrogen of the air. 

It is only within the last few' years that we have 
learned that some plants make use of the nitrogen of 
the air for food. Beans, peas, clover and other plants 
of the botanical family which is known as the 
LEGUMiNOS.'E or PULSE FAMILY, all coutain notably 
large quantities of protein. Yet these crops often 
grow and flourish on soils which will not produce 
crops of wheat, corn, or oats until some nitrogcneous 
fertilizer is added. That the plants of the leguminous 
family could draw on some supply of nitrogen which 
was not available to other crops has been a recognized 
fact for many years. But how or where they got their 
nitrogen was not known until recently. Now, we 
know that leguminous plants obtain parts of their 
nitrogen from the air, and that it is supplied to them 
by bacteria. On the roots of clover, beans, peas, and 
other plants of this family are found, ordinarily, small 
enlargements or knots which are called tubercles. 
These tubercles are the homes of the bacteria whicli 
make the nitrogen compound >< from the nitrogen of 



NITEOGEN IN SOILS 



97 



the air. They fix themselves on the roots, and cause 
the tubercles to grow. This has been proven by grow- 
ing clover or beans in soil known to be free from all 
bacteria. When this was done no tubercles were 
formed on the roots, and the plants made a Very poor 
growth. Fig. 16 shows the tubercles formed on the 
roots of a soy or soja bean plant, which belongs to the 
pulse famil}^ The bacteria which inhabit the roots of 

leguminous plants have the 
power of changing the free 
nitrogen of the air into the 
compounds of nitrogen known 
as nitrates — and these com- 
230unds are readily taken up 
by the plant roots. In this 
way, as it were, the bacteria 
pay rent to the plant for their 
homes on its roots. Why it 
is that these nitrifying bac- 
teria live only on the roots of 
one family of plants is not 
known, but they evidently prefer these plants, for so 
far as we know at present they do not inhabit the 
roots of any other family. The family of leguminous 
plants is a large one, and some of these plants are found 
in all soils and climates. In this Avay nature renews 
the store of nitrogen in the soil, but in cultivated fields 
the conditions are very different. 

Many soils do not contain any of the bacteria which 
change the nitrogen of the air into nitrates. In such 
soils no tubercles form on the roots of legumes, which 
7 




Fig. 16.— Roots of yellow 
soybean, grown at the Kan- 
sas Agricultural Experiment 
Station in 1896, on land inoc- 
ulated with an extract con- 
taining the tubercle-forming 
bacteria. (From Yearbook, 
U. S. Dept. Agr.,1897.) 



98 ELEMENTS OF AGRICULTURE 

plants are in consequence forced to draw their sup- 
plies of nitrogen from the soil, like wheat, oats, or 
an}^ crop having no power to use the nitrogen of the 
air. Without the proper kind of bacteria legumes are 
unable to make any use of the nitrogen of the air. 
To supply deficient soils, these baci^^a are now pre- 
pared for sale, and they may also be supplied by adding 
to the deficient soils quantities of another soil known 
to contain them. It is probable that in a few years the 
various nitrif3dng bacteria will be sold in the market 
much as fertilizers are sold to-day. 

97. Forms of Nitrogen in Soils. — We have learned 
the sources from which the soil is supplied with nitro- 
gen; now, how are these compounds held in the soil? 
A part of the nitrogen is held in the undecayed organic 
matter, some is combined in the humus, and the air in 
the soil contains free nitrogen. In all of these forms 
the nitrogen is unavailable to plants for food, and 
must first be converted into nitrates by the bacteria 
before it may be used. The soil contains some nitrates, 
as does the soil water, but these compounds are in 
small quantities because they are so easily washed from 
the soil. 

Questions 

1. Why is nitrogen particularly important as a plant 
food? 2. From what three sources is the soil's supply of 
nitrogen derived? 3. What happens to the protein com- 
pounds when the plant decays in the soil? 4. What causes 
the decay of plants in the soil? 5. What nitrogen com- 
pounds are formed when plants decay in the soil? 6. What 
is the process of the formation of nitrates called? 7. When 
is nitrification most active? 8. When plants decay is there 



KITEOOEN iX SOILS 99 

ever any loss of nitrogen? 9. Name a family of plants con- 
taining large amounts of protein. 10. Have leguminous 
plants the power of obtaining nitrogen from any other 
source than the soil? 11. How do leguminous plants obtain 
nitrogen from the air? 



L«te. 



100 ELEMENTS OF AGRICULTURE 



CHAPTEE XIX.— How Soils Lose Water 

98. How Soils Become Poor.— The fact that culti- 
vated soils lose their fertility, becoming poor and pro- 
ducing small crops, is only too well known. But how 
this loss of fertility occurs is not so well known, and 
the answer is not easy to find. 

Growing plants are very particular about their food. 
They require a number of different compounds, which 
must be supplied them in certain combinations, else 
the plant will have none of them. If the soil should 
fail to supply the plant with only one of the many 
foods it requires, the plant starves, or if the food be 
supplied in a form not acceptable to the plant, it will 
not take it. For instance, a soil that contains no 
nitrogen, even though it contains every other plant 
food,, cannot grow crops. A soil that contains only 
nitrogen, combined in organic matter and provided 
with no means of forming nitrates will be as barren 
as a desert. Fertile soils are soils that supply all kinds 
of plant foods and supply them in the form most 
acceptable to plants. When the supply of any one or 
more of the foods becomes, from any cause, exhausted, 
the soil is called poor or worn, which means that it 
cannot feed growing plants. The supply of plant food 
in most soils is rarely excessive, and is often small. 
It is an easy matter to exhaust^ by improper methods 



HOW SOILS LOSE WATEK 101 

of cultivation, one or more of the different foods, but 
to renew the supply is not so easy. The two plant foods 
most easily exhausted and most difficult to replace are 
water and nitrogen, and as they are to a certain extent 
dependent on each other, a soil lacking in one is apt 
to be lacking in both. 

99. Moisture Often Lacking in Soils. — The plant 
food most often lacking in soils is moisture. The great 
areas of land known as deserts are deserts because they 
have no supply of water. .The oases of deserts owe 
their existence to a supply of water from some spring 
or well. Provide a desert with a supply of water, and 
it ceases to be a desert, and in time may become fertile. 
In many parts of our country are great stretches of 
land, which, while not reduced to the condition of a 
desert, are so poor that the crops produced are hardly 
worth the gathering. These lands were "once clothed 
with a dense growth of magnificent forest trees: now 
they produce for those who cultivate them the most 
meagre crops. What has caused the change? Has 
the mineral food of the soil become exhausted ? Has 
the nitrogen supply been used up, or has the water 
supply failed? If left uncultivated these lands grow 
up again in trees, and as time passes they become 
clothed again in great forests. Evidently there is 
enough plant food accumulated to produce great crops 
of trees; then why not enough for farm crops? There 
is an ample store of mineral j)laht food in these poor 
soils, but two things are lacking — water -and organic 
matter. But if they arc lacking how can great crops 
of trees grow up? Growing trees add to the soil's 



102 ELEMENTS OF AGKICULTURE 

supply of both water and organic matter, and so in- 
crease its fertility. How they do this is explained in 
succeeding paragraphs . 

100. How the Water Supply of Soils is Renewed. — 
The supply of water in soils is renewed from time to 
time by rains, much of the rain water being held in 
the deep soil as free or ground water. From the deep 
soil it rises into the surface soil as film moisture which 
provides growing plants with a constant supply. The 
more free water a soil holds the greater the store for 
growing plants. If for any reason the free water of a 
soil becomes exhausted the plants growing in the soil 
wilt and die. Growing plants require a constant supply 
of water, which they can obtain only from the film 
moisture of the soil. Eains are often weeks apart, and 
unless water is held by the soil plants suffer. The soil 
below the water table may be considered as a reservoir 
which holds rain water, much as a sponge, and sup- 
plies it as needed to growing plants. If there be a 
leak in the reservoir the water supply is lost. The 
depth of the soil and the number and size of the 
soil particles in a measure determine the amount of 
film moisture a soil is capable of holding. But in 
order that a soil may contain film moisture water must 
be first absorbed and held below as free water. If rain 
water runs off the surface, the soil can contain but 
little moisture. In bare fields this is often the case; 
the rain water runs off the surface, cutting great gullies 
and doing much damage to the land. On land covered 
with growing plants or the litter of dead plants, rain 
water is prevented from running off, and gradually 



HOW SOILS LOSE WATER 103 

soaks into the soil, wliere much of it is lield as film 
moisture. To use a homely illustration, let us suppose 
water is poured on the head of a perfectly bald person ; 
it quickly runs off from his head, falling on his face 
and person, leaving the head scarcely wet. If, on the 
other hand, water is poured on the head of a person 
with a heavy suit of hair, but little runs off till the 
hair is thoroughly wet. This, in a way, illustrates how 
growing plants protect land from washing, and cause 
rain water to enter the soil. 

101. How Growing Plants Stop Surface Evaporation. 
Growing plants, besides protecting the soil from wash- 
ing, prevent excessive surface evaporation, which car- 
ries off much moisture from exposed soils. Sunshine 
and winds are constantly at work evaporating great 
quantities of water from exposed fields, leaving the 
soil dry and hard. On bare fields the loss of water 
through surface evaporation is enormous. To illus- 
trate how this loss takes place, let us suppose we have 
an ordinary bucket half filled with wate::; if left open 
to sunshine and wind the water in the bucket quickly 
evaporates; it passes through the air which fills the 
upper half of the bucket and disappears into the outer 
air as water vapor. If the bucket be covered over to 
protect it from the wind and sun, much of the evapora- 
tion is stopped. N'ow, the soil is much like a bucket half 
full of water. We have first a layer of comparatively 
dry soil, that is soil containing only film moisture. This 
corresponds to the air in the upper half of the water 
bucket. Then we have a layer of soil filled with water, 
and the whole rests on a bottom formed by the imper- 



104 ELEMENTS OF AGRICTTLTUEE 

vious stratum or layer. If the soil is bare and un- 
covered to the sun and wind, the water from below 
rises through the upper layer of soil and evaporates. 
Cover the soil with either growing or dead plants to 
protect its surface, and the evaporation is stopped, as 
it is in the bucket. Anything used to cover the surface 
of the soil to prevent evaporation, or washing, is called 
a mulch, and the process is known as mulching. 

It is in the winter and early spring months that 
most of the rains fall, and in protected soils the excess 
of moisture is stored up for the -use of plants during 
the drier months of summer. If, however, the soil 
be left bare, the winds and sunshine of spring evapo- 
rate vafet quantities, and when summer comes with its 
hot, dry days the growing plants find but a poor supply 
of water stored up for their use. 

102. Condition of Cultivated Fields. — Now, what is 
the condition of many cultivated fields during the 
season of heaviest rainfall? Take the tobacco lands, 
for example; after a crop of tobacco is gathered the 
soil is left almost perfectly bare. Tobacco is gathered 
so late in the season that no weeds can grow, and the 
only protection the soil has from the washing rains 
of winter is the scattered stubble from the crop itself. 
The cotton lands of the South fare but little better 
than the tobacco lands ; their only protection being the 
dry, dead stalks scattered over the fields. Often these 
are collected and burned, leaving the soil with no pro- 
tection for the winter. Wheat and oat lands fare much 
better; for after these crops are cut heavy growths of 
weeds spring up, and these, w^hen plowed under, supply 



HOW SOILS LOSE WATER 105 

the soil with a great mass of decaying organic matter, 
which serves to hold much of the winter's rain, and 
checks surface evaporation. Cultivated soils that have 
an}^ tendency to wash or leach should never be left 
bare to the action of the winter rains. 

Questions 

1. What are fertile soils? 2. If a soil fails to supply any- 
one of the essential plant foods what is it called? 3. How 
does a soil become poor? 4. Name two important plant 
foods often lacking in soils. 5. Why is it that deserts pro- 
duce no plants? 6. How are the oases of deserts formed 
and how may they become fertile? 7. If worn lands are left 
uncultivated for any length of time what sort of crops 
spring up? 8. How is the supply of water in soils renewed? 
9. How is rain water held in soils? 10. How are plants 
constantly supplied with water? 11. Why do soils covered 
with growing plants or the litter of dead plants contain 
more film moisture than bare fields? 12. Give an illustra- 
tion of how plants protect soils from washing, 13. Why do 
lands that have been cropped in tobacco or cotton suffer 
from washing and leaching? 14. Which as a rule contain 
more film moisture, lands left bare all winter or lands cov- 
ered with vegetation? 



106 ELEMENTS OF AGRICULTURE 



CHAPTEE XX.— How Soils Lose Nitrogen 

103. Nitrogen Necessary to Fertile Soils.— Many 

cultivated soils become \\'orii and unfit to produce 
profitable crops through the loss of their supply of 
organic matter which contains nearly all the nitrogen. 
A supply of nitrogen is just as necessary for growing 
crops as a supply of water; and the nitrogen supply of 
soils is to a certain extent dependent upon the water 
supply, because the bacteria which change the protein 
into soluble compounds of nitrogen cannot work in 
perfectly dry soils. In order, then, that soils may con- 
tain nitrogen, they must contain a supply of moisture. 
As cultivated lands are robbed of their water supply, 
becoming hard and dry, they are at the same time 
being robbed of their nitrogen. A dry soil can supply 
the plant with neither water nor nitrogen, and is said 
to be deficient in these two plant foods. 

104. Decay of Organic Matter Necessary to Form 
Nitrogen.— To contain a supply of nitrogen soils must, 
in the first place, contain some form of decaying vege- 
table or animal matter; and, in the second place, in 
order that the organic matter may decay and other 
compounds of nitrogen be formed, the conditions in 
the soil must be favorable to the bacteria which cause 
the changes. 

105. Loss of Nitrogen Through Cultivation.— On 
wooded lands the leaves of the trees die, fall to the 
ground and go to form humus in the soil; the trees 



HOW SOILS LOSE NITEOGEN 107 

themselves in their tnrn die, decay, and pass back into 
the soil; and by this process of gradual growth and 
decay but little nitrogen is lost. But the conditions 
are very different in cultivated fields. Here quantities 
of nitrogen-containing organic matter are each year 
taken from the soil, and but little returned. A crop 
of hay, for instance, weighing about 2,000 pounds, 
takes from the soil about 1,700 pounds of organic mat- 
ter, which contains about twenty-five pounds of nitro- 
gen. And so each crop taken from the soil removes 
a certain amount of nitrogen. Xearly all of this nitro- 
gen comes from the decay of organic matter in the soil, 
and unless fresh organic matter be added to replace 
that used up, the supply must in time become ex- 
hausted, and the bacteria of decay be left without 
material from which to manufacture compounds of 
nitrogen. Suppose a crop removes from the soil twenty- 
five pounds of nitrogen; if the organic matter in the 
soil contains about 1 per cent of nitrogen, such a crop 
would require 2,500 pounds to supply its nitrogen. The 
roots and stubble from crops decay in the soil, and are 
converted into humus and some compounds of nitro- 
gen, but they cannot supply enough nitrogen to replace 
that removed by the crops. After each crop is removed 
the soil should be supplied vfith organic matter which 
may be converted by the bacteria into fresh supplies 
of humus. After some crops, such as wheat and 
oats, crops of weeds spring up, which, when plowed 
under, supply fresh quantities of organic matter. But 
other crops, such as tobacco and cotton, leave the soil 
with only a few scattered roots and stubble. When 



108 ELEMENTS OF AGRICULTUEE 

crops of tobacco or cotton are removed 3^ear after year 
from the same field and no organic matter is added, the 
soil's store of nitrogen soon becomes exhausted. 

106. Denitrification.— But the loss of nitrogen in 
soils occurs not only from a decrease in the supply 
of organic matter. The influence of moisture on nitro- 
gen compounds in soils has already been mentioned. 
Nitrification takes place only in moist soils; in very 
dry soils not only does nitrification cease, but there is 
actually a loss of nitrogen or what is called denitri- 
fication. By a process of dry decay the nitrogen 
compounds in the soil are broken up and the nitrogen 
passes into the air as free nitrogen gas. A loss of 
nitrogen also takes place from very wet soils and from 
soils poorly supplied with air. The water in wet soils 
drives out the air, and without a supply of oxygen no 
nitrates can be formed from the decaying organic 
matter. Some nitrogen compounds are also washed 
from the soil in the drainage water, and some escape 
as ammonia gas. And wdiile the loss in this way from 
ordinary soils is not great, still it is enough to affect 
the total supply. 

Is it any wonder, then, that the cotton and tobacco 
lands become poor, and fail to produce crops ? Washed 
and leached by the winter rains, scorched by the sun, 
parched by the winds, robbed of their water and or- 
ganic matter, how can they produce crops ? 

Questions 

1. How does the loss of organic matter affect soils? 
2. Name two very important plant foods. 3. How does 



HOW SOILS LOSE NITROGEN 109 

the water supply of soils affect the supply of nitrogen? 
4. What three things are necessary for the formation of 
nitrogen compounds in soils? 5. What becomes of the 
dead leaves of trees? 6. What effect do crops have on the 
supply of nitrogen in soils? 7. What is denitrification? 
8. How do dry soils lose nitrogen? 9. How do wet soils 
lose their nitrogen? 10. Why do tobacco lands often suffer 
a greater loss of nitrogen than wheat lands? 11. Why do 
cotton lands suffer a loss of nitrogen? 



110 ELEMENTS OF AGRICULTURE 



CHAPTER XXI.— How Soils Lose Mineral 
Matter 

107. How Cultivation Removes Mineral Matter from 

the Soil. — Soils become impoverished from careless 
cultivation, which causes a loss of water and nitrogen. 
They may also become impoverished through the ex- 
haustion of their supply of phosphoric acid, potash and 
lime. How this occurs may be understood from the 
fact that each crop gathered from the soil uses up for 
its growth and takes with it just so much phosphoric 
acid, potash and lime. A crop of cotton, lint and seed, 
weighing about 1,000 pounds, takes from the soil about 
6| pounds of phosphoric acid and 10 pounds of potash. 
One thousand pounds of tobacco leaves take from the 
soil about 3.4 pounds of phosphoric acid and 40 pounds 
of potash. One thousand pounds of hay take about 
3 pounds of phosphoric acid and 12^ pounds of potash; 
and so each crop takes from the soil var3dng amounts 
of mineral plant food. 

If year after year so much of these plant foods are 
taken away and none returned, the supply must become 
exhausted. As a matter of fact, the available supply 
does often become exhausted. 

108. Phosphates in the Soil. — Phosphorus exists in 
the soil in several forms; combined with certain pro- 
portions of calcium and oxygen it forms a compound 
soluble in water, and in this form is available as plant 
food. Were all the phosphorus in the soil in this form. 



HOW SOILS LOSE MINERAL ^MATTER 111 

what the plants did not use would soon be washed out 
by rains and the soil left with none at all. Fortunately, 
most of the phosphorus in the soil is combined with 
iron and aluminum^ in which form it is nearly insolu- 
ble in water and unavailaljle for plants. By some pro- 
cesses in the soil, probably the action of the acids in 
humus, the insoluble phosphates are gradually being- 
converted into soluble compounds Avhich become food 
for growing plants. This change is so gradual that 
just about enough soluble phosphates are made each 
year to supply the demand of the yearly growth of 
nature's crops. Xature allows her crops to go on 
growing year after year, but little in the way of plant 
food being removed from the soil; so each year only 
enough plant food is required to supply the season's, 
growth, and the supply is always abundant. 

On cultivated lands a crop is usually gathered each 
year, and with it go from the soil the soluble phos- 
phates it has taken up in growing. The next year th j 
soij must supply more plant food for the season's crop, 
and so this goes on each year. The formation of solu- 
ble phosphates in many soils is so slow that there is 
not sufficient to supply this constant demand, and such 
soils are said to be deficient in phosphoric acid. Very 
often they have a large store of insoluble phosphates, 
but are unable to manufacture the soluble compounds 
fast enough to supply the demand of the crops. The 
great store of phosphates contained in most soils is 
shown by the following figures: An acre covers 43,560 
square feet; then if the soil be twelve inches deep, we 
have for an acre of "Tound -13,500 cubic feet of surface 



112 ELEMENTS OF AGRICULTURE 

soil. Now, ordinary soil weighs about 90 pounds to the 
cubic foot. In other words, an acre of soil twelve inches 
deep weighs 3.920,400 pounds. If such a soil contains .1 
per cent of phosphoric acid it would yield 3,920 pounds 
to the acre. Poor, sandy soil contains sometimes only 
0.05 per cent phosphoric acid, or 1,960 pounds to the 
acre. Now, a crop of 1,000 pounds of tobacco removes 
3.4 pounds of phosphoric acid. So an acre of good 
soil contains enough phosplioric acid to sup])ly about 
1,150 crops, of 1,000 pounds each, of tobacco, and poor 
sandy soil has enough for about 575 crops of the same 
size. These figures do not mean that the soil con- 
taining .1 per cent of phosphoric acid could be cropped 
in tobacco, continuously, for 1,150 years without be- 
coming exhausted, for tobacco requires other elements 
besides phosphoric acid; but they do show what a great 
store of j)hosphates the soil contains which, if properly 
used, will furnish many crops with food. But we have 
considered only the first twelve inches of soil; the roots 
of most crops penetrate to greater depths than twelve 
inches; the roots of the cotton plant have been known 
to reach into the subsoil between seven and eight feet. 
The roots of Avheat plants often reach a depth of four 
or even five feet. As the subsoil often contains nearly 
as much of phosphates as the soil, such crops have 
much larger supplies of this food to draw on than are 
contained in the first twelve inches. There is, of course, 
some j^hosphoric acid lost from the soil through leach- 
ing, but as most of the phosphates are very insoluble 
this loss in well cultivated soil is but small. An ordi- 
Tiary soil, if carefully cultivated, may be steadily 



HOW SOILS LOSE MINERAL MATTER 113 

cropped for many generations without exhausting its 
total supply of phosphoric acid, but its supply of avail- 
able phosphates may be exhausted with one or two 
crops. The question, then, is how must the soil be 
treated in order that its store of phosphates may be- 
come available as food for cultivated crops. It is diffi- 
cult to answer this question satisfactorily, for the 
solubility of the soil phosphates is influenced by a 
number of different conditions in the soil, none of 
which is perfectly understood. But it is known that 
the amount of soluble phosphoric acid in soils is in- 
fluenced to a great extent by the amount of humus it 
contains. The so-called insoluble phosphates, though 
almost insoluble in water, are acted on by even weak 
acids, and by them converted into compounds soluble 
in water. Humus contains a number of weak acids, 
and they undoubtedly act on the insoluble phosphates 
in the soil, converting them into forms suitable for 
plant food. Here we have another illustration of the 
value of soil bacteria, and the importance of careful 
cultivation. Soil bacteria supply nitrogen for grow- 
ing crops; they also have much to do with supplying 
the available phosphates. Some salts in the soil proba- 
bly affect the supply of soluble phosphates, but their 
action is not so important as the action of humus. 

109. Potash in the Soil. — The supply of potash in 
the soil comes, as we have already learned, principally 
from the decay of rocks called feldspars, in which the 
potash is combined with silica to form Avhat are called 
potassium silicates. When these rocks decay and form 
soils, some of the silicates combine with clay and form 
8 



114 ELEMENTS OF AGEICULTUKE 

what are called double silicates, which are much less 
soluble in water than the ordinary silicates. In this 
form the}^ are preserved in the soil, and are said to be 
fixed. A good clay loam contains about .5 per cent of 
potash and sandy soils about .1 per cent. This would 
give for the clay soil 19,602 pounds of potash per acre 
of surface soil, and for the sandy soil 3,920 pounds of 
potash. Such a clay soil could furnish enough potash 
for nearly 500 crops of tobacco of 1,000 pounds per 
acre, or 390 crops of hay of two tons per acre. The 
sandy soil could supply potash for about 100 such crops 
of tobacco and nearly eighty such crops of hay. But 
this store of potash is not all available for crops; a 
large part of it is locked up just as the phosphates are, 
and the soil parts with it very slowly. These unavail- 
able compounds of potash become available for plants 
in much the same way as the phosphates, that is, by 
the action of the weak acids of humus. These acids 
form compounds with the potash which are called 
HUMATES, and which are readily taken up by plants. 
Here again, through manufacture of humus, the soil 
bacteria are of great importance. 

110. Lime in the Soil. — Some soils may be deficient 
in their supply of lime, which is an essential plant food. 
Besides being an essential plant food, lime is of great 
value in soils because of its action upon humus. 
Humus, as you have already been told, contains a num- 
ber of weak acids which act on the phosphates and 
potash compounds in the soil. These humus acids also 
combine with the lime in the soil, and by their action 
on the lipie, the phosphates and the potash com- 



HOW SOILS LOSE MINERAL MATTER 115 

pounds, the acid properties of humus are destroyed. 
If a soil contains no lime the small quantities of phos- 
phates or potash compounds usually present are not 
sufficient to combine with all the acids of humus, which 
in consequence go on accumulating until the soil be- 
comes decidedly acid. Now, an excess of these humus 
acids are harmful to the roots of growing plants, re- 
tarding their growth. Xot only are they injurious to 
growing plants, but they are harmful to the bacteria 
that form humus. An animal compelled to live in 
an accumulation of its own manure suffers in health. 
So these bacteria of decay, if compelled to live in an 
excess of the acids which they form, suffer and cease 
to work. Lime acts as a cleansing agent for the bac- 
teria of decay, by absorbing and destroying the waste 
products they produce in the form of acids. A notice- 
able deficiency of lime in soils is shown by an accumu- 
lation of acids. 

111. Life in the Soil. — Most persons look on the soil 
as simply a mass of dead mineral matter and decaving 
parts of plants and animals. But the soil is far from 
being a dead mass. It is the home of countless mil- 
lions of busy workers, bacteria, earth worms and insect 
forms of many kinds. It is a great workshop in which 
the chief workers are the little soil bacteria. It is their 
business to destroy the dead organic matter, manufac- 
turing therefrom valuable compounds of humus and 
nitrogen, and producing acids which change insoluble 
compounds of phosphorus and potash into plant food; 
in short, to keep the soil alive. The materials with 
which the l)acteria work are dead ors^anic matter, water. 



116 ELEMENTS OF AGRICULTURE 

air and heat; and from these they supply the world 
with food. Like all good workers they demand a good 
supply of material, and a comfortable shop well sup- 
plied with fresh air and water. A soil without bacteria 
is as dead as a desert, and incapable of producing 
plants. 

Questions 

1. How does the loss of mineral matter affect the fertility 
of soil? 2. Name three mineral elements which sometimes 
become exhausted. 3. About how much phosphoric acid is 
removed from the soil by 500 pounds of ordinary hay? 
4. How are the unavailable phosphates changed into plant 
food? 5. Why is it an easy matter to exhaust the supply 
of available phosphates in ordinary soil? 6. Why is it that 
available phosphates are not held in the soil? 7. Explain 
why the supply of phosphates in the soil is not exhausted. 
8. Why do cultivated crops take from the soil more plant 
food than crops growing naturally? 9. How far do the 
roots of most plants penetrate the soil? 10. How does 
potash in the soil become available to plants? 11. What 
changes the unavailable potash into available compounds? 
12. How is lime useful to the bacteria in the soil? 

PROBLEMS 

1. If a soil weighs 100 pounds to the cubic foot and con- 
tains 0.15 per cent of phosphoric acid, how many pounds of 
phosphoric acid are contained in an acre of such soil 12 
inches deep? 

2. Calculate the amount of potash in an acre of soil 12 
inches deep when it weighs 95 pounds per cubic foot and 
contains 0.3 per cent potash? 



CULTIVATIOX OF SOILS llT 



CHAPTER XXII.— Cultivation of Soils 

112. Why Soils are Cultivated. — All fertile soils 
produce naturally an abundant growth of plants. This 
growth comes from the seed or roots of the many 
plants which grow naturally in the soil. The seed 
of such plants are scattered over the surface of the 
soil by various means. Many rot, many are eaten by 
birds and animals, and only a few of the total number 
ever grow; but the supply of seed is so great that even 
after allowing for all that are destroyed there are 
enough left to produce many plants. Man grows for 
his use crops of many kinds of plants, most of which 
come from seed. If the seed of these crops useful to 
man are merely scattered over the surface of unculti- 
vated soil, many of them grow, but most of them are 
destroyed, and such methods of crop growing are 
seldom profitable. It has been found much better to 
bury the seed below the surface of the ground, where 
they are better protected from the agents which de- 
stroy them. In order to plant seed successfully the 
surface of the ground must be prepared to receive 
them, and the more thorough the preparation the 
greater the number of seed that grow and the better 
the plants they produce. The various methods of pre- 
paring soils for seed planting are known as cultiva- 
tion. Xot only are soils cultivated to prepare them 
for seed planting, but they are often cultivated to aid 
growing crops in obtaining their food. _ 



118 ELEMENTS OF AGRICULTURE 

We -usually think of cultivation as meaning the pro- 
cess of pulverizing the soil's surface by plowing, 
spading, rolling, etc., and these are the ordinary 
methods employed. But there are other methods of 
cultivation besides mere surface cultivation, and two 
that are oftentimes of great importance are drainage 
and IRRIGATION. They both affect the water supply of 
soils, and water is probably the most important of all 
plant foods. 

113. Drainage. — In Chapter XIX you were told how 
soils lose their water supply, becoming dry and barren ; 
on the other hand, there are soils that contain too 
much water. In many places the impervious stratum 
lies near the surface of the soil, and the soil being shal- 
low, becomes quickly filled with free water. If now 
the impervious stratum has little slope the free water 
drains away very slowly, and the only way the soil is 
freed from it is through surface evaporation, which, 
if the soil be covered with vegetation, is slow. The 
drainage of the soil being poor and the surface evapo- 
ration small, water accumulates and keeps the soil 
constantly wet. It is in this way that swamps and 
marshes are formed. The excessive amount of water 
may be drained from such soils by digging ditches 
through which the water may flow into some creek or 
river. As open ditches interfere with surface cultiva- 
tion, they are usually made into what are called under- 
drains. In the bottom of the ditch a little culvert is 
built of stone, brick or wood, the joints being left open. 
The ditch is then filled in with earth, and tlie under- 
drain is completed. The free water in the soil enters 



CULTIVATION OF SOILS 



119 





the drains through the cracks and joints^ which are 
properly left open. Underdrains are often called 
blind-drains. In place of a built-up drain coarse tiles 
are often used. Tiles are short j^ieces of clay pipe, 
which are loosely fitted together in the bottom of the 
drain. Such drains are called tile-drains, and, as in 
the ordinary drain, the water enters through the joints. 
Fig. 17 shows an ordi- 
nary blind-drain and 
Fig. 18 a tile-drahi. 

Besides removing tlu 
excess of water and ren- 
dering the soil fit for 
surface cultivation, 
drainage is of benefit 
to the soil in several 
ways. It makes the soil 
warmer by preventing the excessive surface evaporation. 
It allows the roots of plants to penetrate the soil to 
greater depths; for the roots of most cultivated crops 
cannot grow in a soil saturated with water. It opens 
up the soil to the air which supplies the roots of grow- 
ing plants with oxygen, and sometimes with nitrogen. 
In many parts of our country are great areas of 
swampy lands which, when properly drained, may be- 
come fertile farming lands. By establishing a thorough 
drainage system the small country of Holland has 
added to its territorv over 12,000 square miles of rich 
farming land that was once an uninhabitable swamp. 
114, Irrigation. — Irrigation is the reverse of drain- 
age, as it is the addition, by artificial means, of 



Stone- 



FiG. 18.— Til ( 
drain. 



120 ELEMENTS OF AGRICULTURE 

water to dry soils. The water is "usually added to the 
soil by means of open ditches. One main channel may 
supply a number of smaller ditches intersecting the 
field to be irrigated, and which need be only a few 
inches deep — little more than an ordinary furrow. 
These irrigation ditches are filled with water from 
some tank or pond, much of which soaks into the soil. 
It is not necessary that these ditches should be kept 
filled with water, for they may be filled from time to 
time, and the water allowed to soak out. This prac- 
tice is called surface irrigation to distinguish it from 
sub-irrigation, by means of which the water is added 
to the subsoil. Underdrains, usually tile, are put in 
with the slope running in the opposite direction to ordi- 
nary drains, and they are occasionally flooded with 
water, which soaks through the joints into the soil. 
This is the most perfect system of irrigation, because 
there is little or no loss of water through surface 
evaporation. Unfortunately, it is mmch more costly 
than surface irrigation, and for this reason but little 
practiced except in gardens or hothouses. 

The flooding of the Nile Yalley is an illustration of 
natural irrigation. This great river annually rises far 
beyond its banks, flooding a great stretch of country; 
the mud it brings with it enriches the soil, and much 
water is at the same time added. The river bottoms 
are thoroughly irrigated once a year, and are noted for 
their fertility. There are in our own county great 
areas of soil that have been robbed of their moisture. 
The rainfall is too uncertain to make good the loss, 
and it is only by irrigation that most of the soil may 



CULTIVATIOX OF SOILS 121 

be made fertile. In many parts of the West large tracts 
of country once parched deserts are being converted 
into fine farming land by means of irrigation. 

Questions 

1. What becomes of most seed simply scattered on the 
surface of the soil? 2. Why is it usually found more pro- 
fitable to bury the seed? 3. Why is it better to prepare the 
soil bei'ore planting seed? 4. By what name do we call the 
process of preparing the soil for planting? 5. What is 
meant by cultivation? 6. Name two important methods of 
cultivation that influence the water supply in soils. 
7. What is meant by drainage? 8. Explain how a swamp 
or marsh is formed. 9. How are open drains made? 
10. What is an underdrain? 11. What is a tile-drain? 
12. How does drainage benefit the soil? 13. What is irri- 
gation? 14. How does surface irrigation differ from sub- 
irrigation? 15. Which is the more perfect system? 16. Why 
is it less used? 17. In what part of the United States it 
irrigation most practiced? 



1^2 ELEMENTS OF AGRICULTURE 



CHAPTER XXIII.— Cultivation of Soils 
(Continued) 

115. Surface Cultivation of Soils. — Surface cultiva- 
tion means the pulverizing of the surface soil prepara- 
tory to planting seed, or else the working of the crop 
after it has begun to grow. The preparation of the 
soil for seed planting is usually accomplished by plow- 
ing. Spading, while it is more efficient than plowing, 
is too expensive to practice on a large scale, and is 
resorted to only for gardens. 

116. Plowing. — Some form of plowing is almost the 
universal method of cultivation, and the plow most 
generally used in this country is the turn plow; that 
is, a plow which turns over the first four to six inches 
of soil. One disadvantage of this form of plow is that 
it cuts usually to the same depth, and after many 
plowings the soil over which the bottom of the plow 
is dragged is apt to become packed, forming what is 
called a hard-pan. This hardened layer of earth is 
difficult for the roots of planta to penetrate, and also 
interferes with the movement of water in the soil. 
It may be broken up by changing the depth of plowing, 
which can be most easily effected by the use of the 
subsoil plow. The subsoil plow follows immediately 
in the furrow of the ordinary plow, and breaks up and 
loosens the subsoil. Subsoil plowing is of benefit when 
the subsoil has a tendency to become hard. 



CULTIVATION OF SOILS 



123 



The plow does not always put the soil into proper 
condition for planting. After plowing, some soils are 
full of lumps and clods, which, unless broken up, 
seriously interfere with the growth of the roots of 
young plants. Such soils are harrowed or rolled for 
the purpose of breaking up the clods and producing 
an even surface. 

117. Cultivating the Soil for Planting. — The pri- 
mary object in sur- 
face cultivation is to 
prepare the soil for 
seed 2)lanting. The 
pulverized surface of- 
fers a safe place for 
the germination of the 
seed, and is easily 
penetrated by the 
young roots. A hard, 
lumpy soil, on the 
other hand, offers a 
poor shelter for seed, 
and retards the development of the roots, producing 
weak, sickly plants. The roots of most cultivated plants 
are soft and delicate, and are entirely unable to 
penetrate hard soils; under such conditions they 
grow slowly and fail to supply the plant with the food 
necessary for its perfect development. Fig. 19 repre- 
sents a plant growing in a shallow, poorly cultivated 
soil, and Fig. 20 represents the same kind of plant 
in a deep, well-cultivated soil. 





Fig. 19.— Plant 

ff rowing in shal- 
ow, poorly culti- 
vated soil. 



Fig. 20.— Plant 
growing in deep, 
well-e ultivated 
soil. 



124 ELEMENTS OF AGRICULTURE 

118. Effect of Cultivation on the Water Supply of 
Soils. — Besides preparing the soil for the development 
of plant roots, cultivation has a marked effect on the 
water supply of soils by increasing the number and 
reducing the size of the soil particles. The effect of the 
number and size of the soil particles on film moisture 
has already been described in Chapter XVII, and the 
effect of drainage on the free water in Chapter XXII. 

119. Aeration.— Surface cultivation also admits a 
freer circulation of air in the soil, by making the sur- 
face more open or porous, thus supplying oxygen for 
the roots of plants and for the soil bacteria. 

120. Cultivation Destroys Insects and Weeds. — Of 
the many kinds of insects that feed on cultivated crops 
there are a number that build their nests in the 
ground, where their eggs are deposited to be hatched 
out by the spring sunshine. Cultivation destroys these 
nests, bringing many insects and their eggs to the sur- 
face, where they are eagerly devoured by birds or killed 
by exposure to the weather. 

Many soils are covered by a growth of weeds which, 
when plowed under, rot and add to the soil a supply 
of humus and nitrogen. If left to grow these weeds 
seriously interfere with the growing crops. 

121. When to Cultivate. — There is great difference 
of opinion as to whether soils to be planted in the 
spring should be plowed in the fall and allowed to lie 
bare all winter, or else plowed a short time before 
planting the crop. As a matter of fact, the time of 
plowing should be regulated by the character of the 
soil. Soils that have a tendency to wash should never 



CULTIVATIOX OF SOILS 125 

be left bare during the winter, but should be by some 
means protected from the winter -rains. There are 
few soils that will not be improved by having their 
surface protected during the winter months by growing 
crops or mulches. Heavy clay soils ma}', however^ be 
improved by fall plowing; as they often have a ten- 
dency to form clods or lumps which are broken up 
during the winter by the action of the weather. Fall 
plowing is also of benefit by destroying insects and 
weeds. 

122. Cultivating the Crop. — After crops have begun 
to grow they are often cultivated for the purpose of 
destroying weeds which spring up along with the crop 
and rob the soil of much food. Such cultivation should 
consist in frequently stirring the surface of the soil 
with a cultivator, harrow, or hoe, care being taken not 
to cultivate deep enough to injure the roots of the 
growing crop. Plowing corn and hoeing tobacco or cot- 
ton are familiar operations to all who have spent any 
time on a farm. Xow, besides destroying weeds, this 
surface cultivation is of much benefit to the crop in an- 
other Avay. Surface evaporation of film moisture, you 
remember, takes place rapidly from exposed soils, and 
the method of cultivation of the three crops just men- 
tioned leaves the soil somewhat bare; at least such is 
the case during the first few months of the crops^ 
growth. The surface cultivation stirs up the first fev/ 
inches of soil, which dry out rapidly and form a sort 
of natural covering or mulch for the soil. It thus 
serves as a check on surface evaporation, and has the 



126 



ELEMENTS OF AGRICULTURE 



same effect as covering the soil with a layer of dry 
earth. 

Crop cultivation also serves to open up the soil to 
a freer circulation of the air which supplies oxygen to 
the growing roots. 

123. Terracing. — There are two methods of treating 
soils to prevent excessive surface washing that are 
especially applicable to steep hillsides. Terracing 
means that the hillside is so cultivated as to form a 
series of large steps or terraces, and the slope between 




Fig. 21.— Terraced hillside, with ditches for irrigating; 
fruit trees planted on the terraces. 

the terraces planted in grass or some thick-growing 
crop to prevent washing. Fig. 21 shows how a hillside 
may be terraced and planted in trees. This is of course 
an expensive method of protecting hills, and a simpler 
and equally as applicable method is to construct a suc- 
cession of smaller terraces about the hill — two good 
furrows forming a terrace a foot or two wide are suffi- 
cient. These are allowed to grow up in grass and serve 
to check the formation of gullies. 

Questions 

1. What is meant by surface cultivation of soils? 2. What 
is the most common method of surface cultivation? 



CULTIVATION OF SOILS 127 

3. What is the most common form of pLow? 4. Explain 
one serious disadvantage of this form of plow. 5. How 
may this trouble be remedied? 6. Why will not a plant 
grow well in a coarse, rough soil? 7. Why do plants as a 
rule develop best in well cultivated soils? 8. What effect 
has good cultivation on the film moisture in soils? 9. How 
does cultivation affect the oxygen supply of soils? 10. How 
does cultivation destroy weeds and insects? 11. How may 
fall plowing benefit heavy clay soils? 12. Under what con- 
dition is it advisable to plow in the fall soils that are to 
be planted in spring? 13. Why are young crops culti- 
vated? 14. How does surface cultivation prevent surface 
evaporation? 15. What is meant by terracing? 16. How 
does terracing protect soils? 



128 ELEMENTS OF AGRICULTURE 



PART IV.— Ma:ntjres 



CHAPTER XXIV.— Classification of Manures 

124. Definition of Manures. — The dictionary defines 
a manure as anything that may be applied to a soil to 
make it more fertile. 

Manures may be conveniently divided into two 
classes^ natural manures and manufactured 
manures; the latter class being called commercial 

FERTILIZERS. 

125. Natural Manures. — These are substances occur- 
ing naturally, and which are not manufactured spe- 
cially for use as manure. Marl, gypsum and some 
forms of potash salts are natural manures, as are wood 
ashes, swamp muck, dead leaves or straw, and, best 
of all, stable manure. .There are some by-products, 
such as cottonseed-meal and sulphate of ammonia, 
which, while not manufactured specially for fertilizers, 
are usually classed with other manufactured products. 

1. Marl is a kind of soft earth, a mixture of sand 
with varying proportions of clay and carbonate of 
lime, with sometimes additions of potash and phos- 
phoric acid. Some kinds found in Xew Jersey and 
Virginia are rich in phosphoric acid and potash, and 
are much used as a fertilizer. Marls, as a rule, are 
used only in the immediate neighborhood of their 
occurrence. Being bulky, the cost of transporting them 



CLASSIFICATIOX OF MANURES 129 

is too great to yield a profit from tlieir sale. The chief 
use of marls is to supply lime to soils. 

2. Gypsum, which when ground up is known as land- 
plaster, is a compound of calcium, oxygen and sulphur. 
It is a soft, white substance easily ground up to a 
powder. Gypsum is used to supply lime to soils. 

3. Wood ashes Avere formerly much used as a fertili- 
zer, but now as wood has become more valuable less 
ashes are produced than formerly. Wood ashes are 
exceedingly valuable for manure, as they contain all 
the mineral elements necessary for plant food. Wood 
ashes all contain a notably large proportion of potash. 

4. Swamp muck is the rich, dark mud that accumu- 
lates in the bottom of ponds and swamps. It is rich 
in organic matter, and is sometimes applied to soils 
poor in humus. 

5. Wood's mold is formed by decaying leaves and 
branches from forest trees, and is used for enriching 
gardens and hotbeds. 

6. Dead leaves, straw and such waste products may 
all be used to supply organic matter to soils. 

7. Barnyard manure is often classed with stable 
manure, though really quite a different product. It is 
the manure that accumulates in small lots where cattle 
are kept and fed, and consists of the droppings of the 
cattle mixed with the bedding supplied them. The 
value of such manure depends both on the bedding 
and the drainage of the lot. When the bedding is thin, 
and the lot well drained, rain water washes away many 
valuable products from the manure. If, on the other 

9 



130 ELEMENTS OF AGRICULTURE 

hand, the lot is well bedded and undrained, the result- 
ing manure is nearl}^ equal in value to stable manure. 

8. Stable manure accumulates in stables where 
animals are kept and fed, and, like barnyard manure, 
is made up of the droppings of animals and the bedding 
supplied them. In some stables the manure is allowed 
to accumulate, fresh bedding being added from time 
to time, until the proper season to apply it to the soil. 
The stables are cleaned out occasionally each year, 
and during the intervals the manure accumulates in 
the stalls. Manure formed in this way has a high 
value; being kept in the stable it is protected from 
the leaching of rain, and, becoming w^ell packed by 
the feet of the animals, is protected from destructive 
fermentation caused by bacteria. The value of stable 
manure depends in a large measure on the kind and 
amount of bedding used, the age and kind of animal, 
and the kinds, and amount of food supplied them. 
Manure from young animals is, as a rule, less valuable 
than manure from maturer animals. As the liquid 
portion of manure contains most of the nitrogen it is 
important that enough bedding be used to absorb and 
retain it. 

When stables are cleaned at short intervals, and it 
is found necessary to keep the manure some time before 
it is applied to the soil, some measure for protecting it 
from the action of the weather must be adopted or a 
loss of valuable compounds of nitrogen results. When 
manure is thrown out it quickly becomes hot, and a 
loss of ammonia results. Anyone familiar with stables 
has noticed how Avarm a manure pile may become, and 



CLASSIFICATION OF MANUKES 131 

that a smell of ammonia is often noticeable. This 
means a loss of much valuable nitrogen, and should, 
if possible, be prevented. 

The loss of ammonia from manure piles is caused 
by the action of a certain class of bacteria, which de- 
stroys the organic matter of manure, forming ammonia 
which passes off as a gas. If the manure pile be pro- 
perly protected the ammonia is retained and changed 
into nitrates. The best known method of protecting 
manure is to compost it. In all cases the manure pile 
should be under a shed or covering of some sort to 
protect it from the weather. 

126. Composting. — The decay of manure is always 
caused by the action of bacteria, and as the manure 
is warmed the action of the bacteria becomes more 
rapid. If the manure pile be thoroughly moistened, 
nitrates are formed by the bacteria just as they are 
formed in the soil when nitrification takes place. If, 
however, the warm pile has been exposed to the sun 
and weather, and has dried out no nitrates are formed, 
but in their place compounds of ammonia which escape 
into the air. An unprotected manure pile may in this 
way become in a short time of almost no value. The 
nitrates which are formed are easily soluble, and unless 
absorbed in some way are rapidly drained away from 
the manure. When nitrates are formed in the soil, 
if not taken up by plant roots they are partly absorbed 
and retained by the soil itself; hence the practice of 
mixing ordinary earth with manure to form a compost 
heap. First a bed is provided from which no drainage 
can take place, and on this is spread a layer of manure. 



132 ELEMENTS 6V AOElCtTLTURE 

The manure is covered with a layer of earth, another 
layer of manure placed on the earth, and this in turn 
covered. The compost heap is made up of alternate 
layers of manure and earth, the earth layers absorb- 
ing the nitrogen compounds formed in the manure. 
For the earth may be substituted plaster, the old mor- 
tar from buildings, or swamp muck. The manure may 
have mixed with it old straw or hay, dead leaves and 
any other refuse matter that can be utilized. Before 
applying to the soil the compost heap should be thor- 
oughly worked over and fermentation allowed to start. 

Questions 

1. What is a manure? 2. Into what two classes are 
manures divided? 3. Name some well-known natural ma- 
nures. 4. What is marl? 5. Why are marls applied to 
soils? 6. What is gypsum, and why is it used for a ferti- 
lizer? 7. Why are wood ashes valuable as a fertilizer? 
8. What is swamp muck, and what makes it valuable as a 
fertilizer? 9. What part of wood's mold, rotting straw, or 
dead leaves is of value as a fertilizer? 10. What is barn- 
yard manure? 11. On what does the value of barnyard 
manure mainly depend? 12. What is stable manure? 
IS. Why is stable manure which is allowed to accumulate 
in the stable of more value than that which is thrown out 
into the weather? 14. What causes the loss of ammonia 
from manure piles? 15. How may the loss of nitrogen be 
prevented? 16. Tell how a compost heap is made. 
17. What substances besides manure may be used in form- 
ing a compost heap? 



COMMEKCIAL FEETILIZEKS 133 



CHAPTEE XXV.— Commercial Fertilizers 

127. Definition of Commercial Fertilizers. — Artificial 
manures, or commercial fertilizers, are such compounds 
as are manufactured expressly for use on soils. They 
may be divided into three classes: 1. Nitrogenous 
fertilizers, including such compounds as are used to 
supply nitrogen, 2. Potassic fertilizers, compounds 
supplying potash. 3. Phosphates, compounds sup- 
plying phosphorus. 

128. Nitrogenous Fertilizers. — Nitrogen compoundc 
are the most exj^ensive of all fertilizers, and as nitrogen 
is often lacking in soils these fertilizers are of the first 
importance. The nitrogen of fertilizers is supplied by 
a number of different compounds, and the more impor- 
tant of these will now be briefly described: 

1. Sodium, nitrate, often called Chile saltpetre, is a 
compound of nitrogen with sodium and oxygen, con- 
taining about 16 per cent of nitrogen. It is a salt and 
resembles in appearance ordinary table salt. It occurs 
naturally in great deposits, the best known of which 
are in Chile; hence its name. It is very impure when 
mined, and before it can be used as a fertilizer must 
be purified. The crude salt is dissolved in water which 
is afterwards evaporated, when tlie purified compounds 
deposit in the form of small crystals. Xitrate of soda 
is easily soluble in water, and as plants take up their 
nitrogen in the form of nitrates, it is ready for the 
use of plants as soon as dissolved in the soil water. 



134 ELEMENTS OF AGRICULTURE 

2. Sulphate of ammonia is another salt containing 
nitrogen, and is nsed to some extent as a fertilizer. It 
is made up of the elements nitrogen, hydrogen, sul- 
phur and oxygen, and contains about 20 per cent of 
nitrogen. Sulphate of ammonia is produced as a by- 
product by gas works which manufacture illuminating 
gas for cities and towns. It is easily soluble in water, 
but in the soil must be changed to a nitrate before it 
becomes plant food. 

Mtrate of soda and sulphate of ammonia are the 
only salts of nitrogen used for fertilizers. A large part 
of the nitrogen of fertilizers comes from organic com- 
pounds, such as cottonseed-meal, bones, dried blood, 
fish scrap, etc. 

3. Cottonseed-meal is a by-product from the manu- 
facture of oil from cottonseed, and is now produced in 
immense quantities. In the oil mills the cottonseed 
first have the hulls — the hard outer shell from which 
the lint grows — taken off by machinery. The soft 
inner portion of the seed, called the kernel, is then 
heated in' immense kettles, after which process it is 
pressed much as apples are pressed for cider, only the 
presses are much more powerful. Most of the oil which 
the seed contains is pressed out by this process, and 
the remainder of the kernels formed into a flat cake 
which from the great pressure is as hard as a board. 
In this form it is called cottonseed-cake, and before 
it can be used must be ground up in mills, from which 
it comes as cottonseed-meal, a substance of a rich, 
golden yellow color, and about as coarse as corn-meal. 

Great quantities of cottonseed-meal are produced 



COMMEKCIAL FERTILIZERS 135 

each year by the oil mills of the South, and each year 
more of it is being used for a fertilizer, especially in the 
cotton States. Cottonseed-meal contains from 7 to 8 
per cent of nitrogen, and, besides this valuable plant 
food, contains 1 to 2 per cent of phosphoric acid, and IJ 
to 3 per cent of potash. When applied to the soil it 
decays rapidly, and, besides the plant food it contains, 
it supplies the soil with much valuable organic matter 
which goes to form humus. 

4. Bones of animals are another source of nitrogen 
for fertilizers. At the bone-yards of large cities, where 
great numbers of dead animals are taken, and at the 
slaughter-houses, where animals are prepared for mar- 
ket, immense quantities of bones accumulate. A part 
of these bones is ground up and sold as a fertilizer 
under the name of raw ground bone. The raw bone 
decays very slowly, and requires a long time before it 
is fit for plant food. Bones are often steamed or 
cooked for the purpose of making glue or oil, and the 
portion remaining after this process is sold as steamed 
BONE. It decays more rapidly in the soil, and is of 
more value as a fertilizer. Eaw ground bone contains 
2J to 4J per cent of nitrogen, steamed bone 1^ to 3J 
per cent. Besides nitrogen, bones contain much phos- 
phoric acid, and are classed as phosphatic fertilizers. 

5. Dried blood is a product of the slaughter-house, 
where quantities of it are dried and sold as a fertilizer. 
Its value depends on its nitrogen, of which it contains 
from 10 to 12 per cent. It decays rapidly in the soil, 
and makes a valuable fertilizer. 

6. Tankage is another product of the slaughter- 



136 ELEMENTS OF AGRICULTURE 

house^ and is made up of the refuse parts .of the 
slaughtered animals. It contains from 10 to 12 per 
cent of nitrogen. 

7. Fish scrap is a by-product from the fish canneries, 
where large quantities of fish are preserved in cans for 
the marl'iet. The refuse parts of the fish are dried and 
sold as a fertilizer. It contains from 7 to 9 per cent 
of nitrogen. 

129. Potash. — Until about forty years ago all the 
potash of fertilizers was supplied by wood ashes, stable 
manure, and waste products, such as rotting straw or 
tobacco stems About the year 1860 there were found 
in Germany, near the town of Stassfurt, great deposits 
of potasli salts, which were probably left there by the 
evaporation of some inland sea or h.ke. Great quanti- 
ties of these potasli salts are now mined and sold, the 
Stassfurt mines supplying potash to the entire world. 
The potash salts as found in the mines are mixed with 
various other compounds, such as common salt, mag- 
nesium chlorides, epsom salts, etc. From this mixture 
pure potash salts are prepared. 

1. Kainit is the crude salt as it comes from the mine 
and contains a number of different compounds. Most 
of the potash in kainit is in the form of a sulphate; 
that is, it is combined with sulphur and ox3\gen. It 
contains only about 12 per cent of potash. 

2. Sylvinit is another of the crude salts, and most 
of the potash it contains is in the form of a chloride. 
S3dvinit contains from 15 to 20 per cent of potash. 

3. Muriate of potasli, which is mannfactured from 
the crude salts, such as kainit, is a compound of potas- 



COMMERCIAL FERTILIZERS 



isf 



sinm with chlorine, and is more properly called potas- 
sium chloride. It is one of the best known potassium 
fertilizers, and contains about 50 per cent of potash. 

4. Sulphate of potash is a compound of potassium 
with sulphur and oxygen, and is also manufactured 
from the crude potash salts. It contains about the 
same amount of potash as the muriates, and is much 
used as a fertilizer. 

Questions 

1. What are commercial fertilizers? 2. Into what three 
classes may they be divided? 3. What two inorganic sub- 
stances supply nitrogen compounds for fertilizers? 4. Why 
is nitrate of soda called Chile saltpetre? 5. When is nitrate 
of soda suitable for plant food? 6. Tell what you know 
about sulphate of ammonia. 7. How is cottonseed-meal 
obtained from cottonseed? 8. About how much nitrogen 
does cottonseed-meal contain? 9. With what other valu- 
able compound does it supply the soil? 10. Name four 
other organic substances used to supply nitrogen. 11. From 
what country do most potash salts come? 12. Name 
two of the crude products, and tell how much potash each 
contains. 13. What is muriate of potash, and how much 
potash does it contain? 14. What is sulphate of potash, 
and how much potash does it contain? 



138 ELEMENTS OF AGEICULTURE 



CHAPTER XXVI.— Commercial Fertilizers 
(Continued) 

130. Phosphates. — The phosphates of fertilizers 
comes from two sources: (1) The great deposits of rock 
phosphate; (2) The hones of animals. 

131. Where Phosphates are Found. — Phosphate rock 
is found in many parts of the world. In Canada there 
are large deposits of mineral phosphates called 
APATITE. In the United States great quantities of 
phosphates are found, the hest known deposits occur- 
ring in the States of Xorth Carolina, South Carolina, 
Florida and Tennessee. In the United States the 
deposits are known as phosphate rock. 

Phosphate rock varies greatl}^ in appearance and 
composition, and occurs sometimes as pehhles in hot- 
toms of rivers, sometimes as houlders scattered 
through the soil, and again as great heds of rock re- 
semhling heds of limestone. In the States of South 
Carolina, Xorth Carolina and Florida the deposits of 
phosphates are, as a rule, found near the coast. The 
so-called river rock is dredged from the hottom of 
rivers, some in the form of water-worn stones, and 
some in houlders of various sizes, which are taken from 
the mud of the river hottoms. The land rock occurs 
in masses varying in size from small stones to boulders 
weighing many tons. 



COMMERCIAL FEETILIZERS 139 

132. Appearance of Phosphate Rock. — In appear- 
ance phosphate rock varies greath'. The soft, white 
j^hosphates of Florida resemble marl, and are nearly 
as soft. The Tennessee rock, as a rule, is hard and 
resembles in appearance ordinary limestone. The ordi- 
nary South Carolina rock is between these two ex- 
tremes, being of a dirty gray color and moderately 
hard. 

133. Composition of Phosphate Rock. — All phos- 
phate rock, wherever it occurs and whatever its appear- 
ance, contains some compounds of phosphorus, and its 
value as a fertilizer depends on the amount and condi- 
tion of these compounds. Most of the rock used for 
fertilizers contains j)hosphorus combined with calcium 
and ox3'gen, which compound is known as calcium 
phosphate or bone phosphate. Some samples of phos- 
phate rock contain as much as 98 per cent calcium 
phosphate, and some rock contains almost none at all. 
Good rock should contain at least 50 per cent of cal- 
cium phosphate. Part of the phosphorus may be com- 
bined with iron and aluminum, and is then known as 
iron and aluminum phosphate. The best grades of rock 
contain but little iron and aluminum, but in some 
varieties of rock all the phosphorus is combined with 
these two elements. Such rock, while of some value 
for fertilizers, is not nearly so valuable as the calcium 
phosphate rock. 

Besides compounds of phosphorus, phosphate rock 
contains varying quantities of sand, organic matter, 
iron and sulphur, and minute quantities of several other 
substances. 



140 ELEMENTS OF AGRICULTURE 

134. Manufacture of Commercial Phosphates. — The 

phosphorus compounds in ^^hospliate rock are practi- 
cally insoluble in water, and before they can become 
plant food must be changed into soluble compounds. 
Where phosphate rock is applied to soils the weak acids 
in the soil gradually change the insoluble phosphates 
into soluble compounds, but the change is slow at best. 
Now% strong mineral acids, such as sulphuric acid — 
oil of vitrol — have the same effect as the weak soil acids 
on the insoluble phosphates, changing them into soluble 
compounds, and the stronger the acid the more rapid 
the change. This fact is taken advantage of in the 
manufacture of phosphates, and the process is briefly 
as follows : The phosphate rock, after being cleaned, is 
ground to a fine powder in powerful mills, and this 
powder mixed with strong sulphuric acid. When the 
acid is mixed with the dry powder it first forms a sticky 
mass like stiff mud; this is thoroughly worked up and 
allowed to stand in order to give the acid time to 
change all the insoluble compounds into soluble. The 
sulphuric acid in changing the phosphate compounds 
is itself changed into calcium sulphate, or gypsum. The 
change in the sulphuric acid is necessary, for the acid 
itself destroys all vegetation, and any unchanged acid 
would ruin the fertilizer. The amount of acid neces- 
sary to form the soluble phosphates is carefully deter- 
mined beforehand, and the right amount added. After 
the mixture has stood the proper length of time it 
becomes about as dry as ordinary soil, and all the acid 
is neutralized, i. e., changed into sulphate. The phos- 



COMMERCIAL FERTILIZERS 141 

phate is now placed in sacks and sold as acid phos- 
phate, DISSOLVED BONE, DISSOLVED ROCK, ctC. 

There are three kinds of phosphorus compounds in 
acid phosphate, and they are known as: (1) Soluble 
PHOSPHORIC ACID, wliich is easily soluble in water; 

(2) reverted PHOSPHORIC ACID, which is easily 
soluble in weak acids, such as are found in the soil; 

(3) INSOLUBLE PHOSPHORIC ACID, which is solublc in 
strong acids. The insoluble phosphoric acid is part 
of the original ground rock which has not been acted 
on by acids; it forms but a very small part of good 
fertilizers, seldom above 1 per cent. The soluble and 
reverted phosphoric acids are classed together as avail- 
able PHOSPHORIC ACID. The sum of the available and 
insoluble gives what is called the total phosphoric 

ACID. 

135. Bone Phosphate. — The bones of all animals 
contain large amounts of phosphate of lime, and are 
much used for fertilizers. When the bones are simply 
ground and sold for a fertilizer the product is known 
as raw bone, and nearly all of the phosphoric acid it 
contains is insoluble. The steamed bone, while it is 
made up principally of insoluble phosphoric acid, de- 
cays much more rapidly in the soil, and for this reason 
is of more value as a fertilizer. As a large part of the 
organic matter has been removed by the process of 
cooking, steamed bone contains more phosphoric acid 
than raw bone. Eaw bone contains 20 to 25 per cent 
of phosphoric acid, or 43 to 51 per cent of bone phos- 
phate. Steamed bone contains 22 to 29 per cent of 
phosphoric acid, or 48 to 63 per cent of bone phosphate. 



142 ELEMENTS OF AGRICULTURE 

136. Valuation of Fertilizers. — Commercial fertili- 
zers are valued according to the. amounts of nitrogen, 
phosphoric acid and potash they contain, and, in order 
to protect the consumer from dishonest manufacturers, 
most States have employed chemists whose business it 
is to examine all fertilizers sold in their State, to see 
if they contain what the manufacturers claim for them. 
Each 25ackage of fertilizer sold must have printed on 
it the amounts of nitrogen, phosphoric acid, and potash 
it contains, so that buyers may know what they are 
getting. Each State chemist fixes a value per pound 
for nitrogen, phosphoric acid and potash, and with 
them anyone may calculate the value of any commer- 
cial fertilizer. Suppose, for instance, that nitrogen 
is valued at 15 cents a pound; then if a fertilizer con- 
tains 2 per cent of nitrogen its supply is worth $G.OO 
per ton. If the fertilizer contains also 8 per cent of 
available phosphoric acid which is valued at 4 cents 
a pound, its supply of phosphate is worth $6.40 per 
ton. If, besides nitrogen and phosphoric acid, the fer- 
tilizer contains 1 per cent of potash valued at 5 cents 
a pound, its potash is worth $1.00 per ton, making a ton 
of the fertilizer worth $13.40. 

Nitrogen, 2% of 2,000 lbs. =40 lbs. at°,15^ per lb. = $ 6 00 
Phosphoric acid, 8% of 2,000 lbs. = 160 lbs. at 4<? per 

lb. = 6 40 

Potash, 1% of 2,000 lbs. =20 'lbs. at 5^ per lb. = 1 00 



$13 40 



The valuations placed on nitrogen, phosphoric acid 
and potash by official chemists are based upon the 



COMMERCIAL FERTILIZERS 143 

wholesale prices of these substances at points of suppl}^ 
For instance, if nitrate of soda sells for $48 a ton, and 
contairis 16 per cent of nitrogen, then its nitrogen is 
worth 15 cents a pound. If cottonseed-meal sells for 
$18 a ton, and contains 6.75 per cent of nitrogen, then 
its nitrogen is worth 13.3 cents a pound. In the same 
way, values are fixed for the phosphoric acid and potash 
supplied b}^ various substances. These values are 
usualh' fixed once each season, and remain unchanged 
until the next season. 

When the various substances supplying nitrogen, 
phosphoric acid and potash are mixed to form a com- 
plete fertilizer — that is, a fertilizer containing all of 
these plant foods — the valuations of the official chem- 
ists may be used to estimate the cost of the raw 
materials, as in the example already given. The selling 
price of the fertilizer is, however, often greater than 
the estimated value of the raw materials, because the 
manufacturer charges enough to insure himself a profit 
after paying the cost of manufacturing and of placing 
the fertilizer on the market. 

Neither the valuation of the official chemist nor the 
market price indicates, however, the agricultural value 
of any fertilizer, for its agricultural value can be deter- 
mined only by actual tests in the field. The published 
analyses and the official valuations of fertilizers are, 
however, of benefit to the farmer in several ways. 

They show, first, what the composition of a fertilizer 
is, and whether it fulfills the claims of the manufac- 
turer. Next, by showing the farmer how to calculate 
ior himself the market value of the guaranteed con- 



144 ELEMENTS OF AGKICULTUKE 

stituents of a fertilizer^ they enable him to tell whether 
the manufacturer is charging too much for his article, 
and what are the relative values of different brands of 
fertilizers. iVnd, finally, they warn the farmer that 
there is very little in a name or brand, for in not a few 
instances manufacturers have been known to sell the 
same article under many different names or brands. 

Questions 

1. From what two sources are the phosphates of ferti- 
lizers derived? 2. Name the States in which the best 
known deposits of phosphate rock are found. 3. What is 
the difference between land rock and river rock? 4. How 
does the land rock usually occur in the soil? 5. How does 
the phosphate rock from different localities differ in ap- 
pearance? 6. All phosphate rock contains compounds of 
what element? 7. With wliat two elements is the phos- 
phorus of phosphate rock usually combined and what is the 
compound called? 8. On what does the value of phosphate 
rock principally depend? 9. About how much calcium 
phosphate should good rock contain? 10. With what other 
elements is a part of the phosphorus combined? 11. How 
are the insoluble phosphates changed into soluble com- 
pounds in the soil? 12. Describe the process of manufac- 
turing soluble phosphates. 13. What becomes of the sulphu- 
ric acid used to make soluble phosphates? 14. What are the 
soluble phosphates called? 15. What is meant by soluble 
phosphoric acid, what by available, and what by total? 
16. What is the difference between raw bone and steamed 
bone? 17. About how much calcium phosphate does each 
contain? 18. How are fertilizers valued? 

PROBLEM 

Calculate the value of a ton of fertilizer containing 3 per 
cent nitrogen, 9 per cent available phosphoric acid, and 2 
per cent potash; nitrogen being valued at 14 cents a pound, 
phosphoric acid at 4 cents, and potash at 5 cents. 



USE OF MANURES 145 



CHAPTER XXYII.— Use of Manures 

137. Purpose of Manures. — The purpose of applying 
manures is always to increase the yield of cultivated 
crops. The manures may be applied to furnish food 
for some one particular crop, or they may be used to 
increase the fertility of the soil, but in each case the 
object is the same. Manures that are used to furnish 
plant food for some one particular crop are called 
SPECIAL MANURES. Manures that are used to improve 
the condition of the soil are called general manures. 
For special manures only such compounds as furnish 
easily available plant food are used. For general 
manures substances are used which increase the store 
of plant food in the soil, either by being gradually 
changed into plant food themselves, or by forming 
available compounds with the unavailable plant food 
already in the soil. The process of increasing the fer- 
tility of worn soils is called soil restoration. 

138. Restoration of Worn Soils. — A worn soil is one 
that for some reason fails to produce profitable crops. 
This failure to produce crops may arise from poor culti- 
vation, or it may be that one or all of the different 
compounds supplying available plant food are lacking; 
but whatever the cause, the trouble should be known 
before a cure is attempted. The successful physician 
always learns, if possible, the nature of his patient's 
illness before attempting a cure, and so should those 
10 



146 ELEMENTS OF AGRICULTUEE 

who expect to cure sick soils know the cause of the 
trouble before applying remedies. 

There are many ways in which a soil may become 
poor, but, as already pointed out, the loss of moisture 
and organic matter is the chief cause of poor soils. 
Therefore, in improving a poor soil, the first point to 
be inquired into should be its supply of water and 
organic matter. A soil well supplied with organic 
matter is, if well cultivated, usually well supplied with 
water and plant food; so it is safe to begin the 
improvement of worn soils by looking to the supply of 
organic matter. Increase the soil's supply of organic 
matter, and you increase its supply of moisture and 
plant food. The usual method of increasing the soil's 
store of organic matter is to grow some crop and plow 
it under while it is growing. Leguminous crops, such 
as clover and beans, are the best for the purpose, as 
they gather from the air stores of nitrogen which, 
when they decay, are added to the store in the soil. 
The plowing under of growing crops is called green 
MANURING, and is much practiced on worn soils. The 
green crops, decaying in the soil, form valuable com- 
pounds of nitrogen and humus. The humus increases 
the soil's power to hold water, and combining with 
the insoluble phosphates and potash compounds in the 
soil forms available plant foods. As the organic matter 
of the green manure decays slowly, and the humus 
which is formed acts slowly on the insoluble com- 
pounds, the good effects of one application of green 
manure may last throughout several years. For green 
manuring there is no better crop than the old-field pea, 



USE OF MANURES 147 

or cowpea. It will grow in a very poor soil and add 
greatly to its store of nitrogen. 

The addition to the soil of stable manure accom- 
plishes the same purpose as plowing under green crops; 
indeed it does more^ for it adds to the soil some useful 
compounds of phosphorus and potash and a host of 
useful bacteria. Stable manure is both a special and 
general manure; it adds to the soil compounds that 
soon become available for plant food, and also grad- 
ually improves the condition of the soil. Stable manure 
is probably the most valuable of all manures, and may 
be used to great advantage on most soils. It should 
be regarded as one of the most valuable products of the 
farm, and should never be w^asted. 

Organic matter and moisture, however, r.re not the 
only plant foods that may be lacking in poor soils; some 
one or more of the mineral elements may be wanting. 
Thus there are soils in which the supply of lime has 
become exhausted, and where this is the case the soil, 
from the accumulation of humus acids, usually becomes 
sour. This acidity may be corrected by the application 
of lime. Soils rich in decaying organic matter are often 
improved by an application of lime. 

The total supply of phosphoric acid and potash in 
soils is seldom exhausted, though such cases do occur. 
The available phosphoric acid and potash, on the other 
hand, are often exhausted, and must be renewed either 
by the application of a fertilizer, or by treating the soil 
so as to render the insoluble com|)ounds available. 

When a soil becomes worn and poor it should be 
carefully examined, and, if possible, tlie cause of the 



148 



ELEMENTS OF AGRICULTURE 



trouble ascertained; then the proper course of treat- 
ment may be determined on. It is no simple matter 
to restore the fertility of a worn soil, and there are no 
fixed rules to be followed; each individual case must 
be carefully studied and treated. Very often the proper 
treatment can be determined only by experiment. 

139. Special Manuring. — In using special manures 
the manure is added for the benefit of some one par- 
ticular crop, and it is of more importance to know the 
needs of the crop in question than it is to know the 
needs of the soil. For instance, clover and cowpeas are 
crops which require large amounts of nitrogen com- 
pounds for their production, but which are able to draw 
on the atmosphere for a large part of their needs. It is 
therefore useless to supply such crops with nitrogenous 
manures. The soil may be very poor in nitrogen, but 
that is of little consequence so far as these crops are 
concerned; they are to a certain extent independent of 
the soil for their nitrogen supply. Again, 1,000 pounds 
of tobacco leaves require for their production 40 
pounds of j^otash and only 3.4 pounds of phosphoric 
acid. It is evident that tobacco requires for its pro- 
duction more potash than phosphoric acid, and we may 
use this knowledge in preparing a fertilizer for use on 
this crop. 

When manures are applied to increase the yield of any 
particular crop, it is the crop that is to be fed, and not 
the soil. By analyzing the crop in question we may learn 
the amounts of plant food it requires for its produc- 
tion. Now, it would seem an easy matter to analyze 
the soil and find out what it lacks in the way of plant 



USE OF MANURES 149 

food, and with this information and the knowleage of 
what the crop in question requires, apply the proper 
amounts of the fertilizers. The difficulty in the way 
is, tliat while it is possible to determine with consider- 
able accuracy how much nitrogen, phosphoric acid, 
potash, lime, etc., a soil contains, there is no accurate 
method for determining just how much of each of these 
substances is in available form for plant food. We 
may find by analysis that a soil contains .5 per cent 
of potash, but for all we know from the analysis, the 
total amount may be unavailable for plants. On the 
other hand, we do know from accurate analyses just 
how much plant food is required to produce any single 
crop, and can use the knowledge to advantage in apply- 
ing fertilizers. 

But different plants vary greatly in their power of 
procuring their food supplies from the soil; one, for 
example, requiring large amounts of potash may be 
able to obtain its supply of this constituent much more 
easily and readily than another requiring a smaller 
amount of it. In such cases analysis is not a safe guide. 

Xo fixed rules can be laid down for the use of 
manures; different crops require very different treat- 
ment, and even the same crop under varying conditions 
of soil and climate takes up varying amounts of plant 
food. The only reliable way of determining what dif- 
ferent crops require in the way of plant food is by 
experiment. Every farmer must determine for himself 
the kind and amount of fertilizer his crops require, and 
in doing this he may be greatly aided by a knowledge 
of the composition and habits of growth of the crops. 



150 ELEMEA^TS OF AGRICULTURE 

Questions 

1. What is the object in applying manures to soils? 
2. What is meant by a general manure? 3. To what kind of 
soils are general manures usually applied? 4. When is a 
soil said to be worn? 5. In restoring a worn soil what is 
the first thing to be considered? 6, Name two of the chief 
causes of poor soils. 7. What is the usual method of in- 
creasing the organic matter in the soil? 8. What is the 
process called? 9. How does the plowing under of a green 
crop improve a poor soil? 10. Why is stable manure of 
benefit to poor soils? 11. What are the best crops to use for 
green manure? 12. What effect does the loss of lime have 
on the soil? 13. How may acid soil be improved? 14. What 
is meant by a special manure? 15. Special manures should 
contain the plant food in what form? 16. How does a 
knowledge of the composition of crops aid in determining 
the application of special manures? 17. Why can you not 
lay down fixed rules for the application of manures? 



SEED TESTING 151 



PART v.— F^RM Crops 

CHAPTER XXVIII.— Seed Testing 

140. Primary Object of Agriculture. — Professor S. 
W. Johnson, one of our foremost writers on agricul- 
tural subjects, thus defines the object of agriculture: 
" The object of agriculture is the production of certain 
plants and certain animals which are employed to feed, 
clothe and otherAvise serve the human race. The first 
aim, in all cases, is the production of plants.^'* The 
successful farmer should then strive to produce, at the 
smallest possible cost, the largest crops of certain 
plants. In order to produce the largest crops he must 
know something of the habits and needs of the plants 
in question. It would be unwise to attempt to grow 
rice or cotton in Maine, or sugar beets in Florida ; nor 
would it be advisable to attempt to grow celery in a 
dr}", sandy soil, or sweet potatoes in a cool, damp soil. 
Each plant has its preference in regard to soil and 
climate, and each requires for its proper growth and 
development certain kinds of plant food. The study 
of agriculture among other things endeavors to find out 
the various requirements of different farm crops, and 
to make rules for their cultivation which, if properly 
observed, will produce the largest possible crop at the 
least cost. 



*How Crops Grow, by S. VV. Johnson, page 1. 



152 ELEMENTS OF AGRICULTURI! 

141. General Farming and Special Farming. — On 

many farms are produced each year several different 
kinds of crops; such as wheat, corn, tobacco, and oats. 
This practice is called general farming. But gradu- 
ally the production of one main crop on each farm is 
becoming customary. In addition to such crops as are 
needed to feed themselves and their stock, many plantr 
ers raise for the market only one main crop, as for ex- 
ample, cotton, rice, or tobacco. This is called special 
FARMING. The kind of crops the farmer raises is usually 
determined by his soil and climate, and by the demands 
of the market. 

142. Selecting Seed. — After determining on the 
kind of crop to be planted, and after preparing the 
soil in which to plant it, the next important step is 
selecting the seed; and in doing this it is important 
to remember that poor seed produce poor crops. Select 
only good, pure seed for planting. Seed are unfit for 
planting: (1) When they come from diseased or ill- 
shaped plants, (2) when they are not fully matured, 
(3) when they are too old, (4) when they have been 
attacked by disease or insects, (5) when they are small 
and ill-shaped, (6) when they are mixed with other 
seed or trash. 

143. How to Test the Purity of Seed. — The first 
thing to do is to weigh the seed. The seed of different 
crops vary in weight, and the weights per bushel for 
pure seed have been determined for most farm crops. 
These standard weights are given in a table in the 
appendix. If the sample of seed to be tested does not 
agree in weight with the standard, then it is reason- 



SEED TESTING 153 

able to suppose that something is wrong, and further 
test should be made. ^Yhateve^ the weight of the seed, 
it is well to take a small amount, say an ounce, exam- 
ine it carefully and pick out all the trash, unsound 
seed, and foreign seed. Foreign seed mean any seed 
other than the kind called for by the sample. By 
weighing the impurities the per cent of pure seed may 
be determined. 

144. Germinating Tests for Seed. — The most im- 
portant test for seed is determining their power to ger- 
minate, that is, their power to grow when planted. The 
seed may be apparently sound and contain almost no 
trash or impure seed, and yet fail to grow when planted. 
Old seed often fail to grow. A simple method of germi- 
nating seed was described in the experiment on page 
36, and it is well to test all seed in this way before 
planting. Take say 50, 100, or 200 seed, depending on 
their size, and germinate them as described in the ex- 
periment. By being careful to have all the conditions 
of temperature and moisture just right, and by noting 
the number sprouting, the per cent of sound seed may 
be determined. 

145. Necessity for Testing Seed. — It is unfortu- 
nately true that many kinds of seed are adulterated, 
some by accident, others by design. Small seed, such 
as grass or clover seed, are easily adulterated, and the 
impurities are difficult to detect. The U. S. Depart- 
ment of i\griculture at Washington has made trials 
of many kinds of seed, and Fig. 22 shows the result 
of a test of red clover seed. Only 46.2 per cent of 
the seed bought could be relied on to srrow when 



154 



ELEMENTS OF AGRICULTURE 



planted. " More than one-half of the total was waste, 
or worse, making the actual cost of the good seed more 
than double the amount supposedly paid for it."* The 
market price of the seed was $3.50 per bushel, but as 
more than half, 53.8 per cent, of this amount was 
waste, the good seed actually cost $7.5G per bushel. 
Many examples of this kind might be given to show 
the necessity for seed testing. Of course all the seed 

sold on the market are not 
so bad as the samjile used 
in this test. Some lots of 
seed are very good, and con- 
tain almost no impurities. 
On the other hand, there 
are other lots of seed much 
worse than the one cited. 
For example, the U. S. De- 
partment of Agriculture 
found one sample of clover 
seed that contained only .8 
per cent of pure, germinable 
seed. The market price of 
this seed was 15.75 per bushel, but the actual price for 
the good seed was at the rate of $703.80 per bushel. 

146. Deterioration of Seed. — Good seed as a rule 
produce good crops, which, in turn, produce good seed. 
But this is true only when the crop is grown under 
favorable conditions. Poorly cultivated crops pro- 
duce a poorer quality of seed than those from which 



Fig. 22.— Red clover {Trifolium 
pratense): 1, one pound of seed as 
bought; 2, pure seed; 3, broken 
seed and dirt; 4. spurious seed; 
5, total waste; G, pure and germi- 
nable seed. (From Farmers' Bul- 
letin, No. Ill, U. S. Dept. Agr.) 



^Farmers' Bulletin No. Ill, U. S. Dept, Agr., 1900. 



SEED TESTING 155 

the}^ grow, and the quality is said to deteriorate. Seed 
from crops grown in a cold climate when planted in a 
warm climate often produce an improved quality of 
seed. On the other hand, seed taken from a warm 
climate to a cold often produce an inferior quality 
of seed. Good seed deteriorate when planted in un- 
suitable soils, or in soils not well supplied with the 
proper plant foods. All farms crops originally grew 
wild. Man found them useful and cultivated them. 
By great care in selecting and planting only the best 
seed and by thorough cultivation, the quality has been 
steadily improved and is still being improved. But it 
is only by constant attention that they are kept up to 
their improved condition. If neglected they soon be- 
come as poor as they were originally. 

EXPERIMENT 

Purchase an ounce of grass or clover seed from some dealer. With 
the class, pick over (lie seed carefully, separating the good, sound seed 
from the trash and foreign seed. Weigh the sample and determine 
fjie per cent of sound '<eed. Sprout 100 of the sound seed and note 
Ihe number germinating. 

Questions 

1. What is the primary object of agriculture? 2. Why is 
it advisable to know something of the habits of the plants 
grown for use on the farm? 3. What is general farming? 
4. What is special farming? 5. After preparing the soil 
and determining on the kind of crop, what is the next step? 
6. In selecting seed, what are some of the points to be con- 
sidered? 7. How may seed be tested for purity? 8. How 
may the germinating power of seed be tested? 9. What 



156 ELEMENTS OF AGEICULTUEE 

was the result of the test of red clover seed by the United 
States Department of Agriculture? 10. What is meant by 
the deterioration of seed? 11. What are some of the causes 
of the deterioration of seed? 

PROBLEM 

Suppose we buy 10 pounds of seed at 14 cents a pound. 
After testing we find that the lot contains only 46 per cent 
of seed that will grow. What is the cost of the good seed 
a pound? 



CEREAL AND FODDER CROPS 157 



CHAPTEE XXIX.— Classification of Crops: 
Cereal and Fodder Crops 

147. Classification.— There are so many kinds of 
crops grown on the different farms of this country 
that to attempt to describe each one separately would 
require too much space and time. Fortunately for our 
purpose many of these crops are alike in their manner 
of cultivation and growth, and we may arrange the 
more important farm crops into a few classes. 

The grain crops, Indian corn, wheat, oats, rye, bar- 
ley, etc., are all ])laced in one class and called cereal 
CROPS. Crops grown for hay, fodder, or pasture are 
all called forage crops. Crops grown for their roots 
or tubers, such as potatoes, turnips, beets, etc., are 
called ROOT and tuber crops; and the crops not in- 
cluded in any of these classes are described as mis- 
cellaneous crops. We have then: 

1. Cereal or Grain Crops: Indian corn, wheat, oats, 
rye, barley, rice, etc. 

2. Forage Crops: clovers and grasses for hay, fod- 
der, and pasture. 

3. Root and Tuber Crops: beets, turnips, potatoes, 
etc. 

4. Miscellaneous Crops: tobacco, cotton, fruit crops, 
garden crops, etc. 

148. Cereals. — The three important cereal crops of 
this country are Indian corn, wheat, and oats. Rice 



158 ELEMENTS OF AGRICULTUEE 

is also an important grain crop, but its growth is lim- 
ited to a small section of country. By the word corn 
in the United States is meant Indian corn or maize. 
In many foreign countries the word corn means the 
seed of all cereal plants — wheat, rye, oats, barley, and 
Indian corn. The word corn as we shall nse it always 
refers to Indian corn. 

The cereal crops are grown for the seed they pro- 
duce. It is true that both corn and oats are some- 
times grown for fodder, but their chief value to man 
lies in their seed. 

Corn, wheat, and oats are found growing in all the 
temperate regions of the earth, in many different 
kinds of soil and in many climates. The numerous 
soils and climates in which the crops grow have pro- 
duced a number of different varieties; thus we have 
dent corn, flint corn, popcorn, etc.; red wheat, white 
wheat, bearded wheat, etc.; and many varieties of oats. 
But while these varieties differ somewhat in appear- 
ance they are very similar in habits of growth and food 
requirements. 

All the cereals are annuals, and have clustered or 
crown roots, as shown in Fig. 5, page 40. These roots 
branch out near the surface and spread through the 
surface soil. Some of the roots penetrate to consid- 
erable depths in the subsoil; the roots of winter wheat- 
plants have been known to penetrate the soil to a 
depth of four feet or more, but most of the roots 
draw their supplies of food and water from the upper 
soil. 



I 



CEREAL AND FODDER CROPS 159 

The cereal crops grow on almost any kind of soil, 
but they do best in deep, rich, clay loams which are well 
supplied with water, but not wet. The ideal soils for 
cereals are the rich prairie soils of the western United 
States and eastern Russia. Whatever the kind of soil 
in which these crops are to be grown, it should be well 
cultivated in order to give the roots a chance to spread. 
Hard, rough soils give the roots of cereals no chance 
to spread in search of food, and the crops suffer in 
consequence. Light, sandy soils contain neither suffi- 
cient food nor water for the cereals. The cereal crops 
are best planted in drills or rows. When planted in 
this Avay a better yield of grain per acre is obtained 
than if the seed be scattered over the surface. 

The cereal crops recjuire an abundant supply of 
nitrogen, phosphoric acid, and potash, all of which 
they draw from the soil. If the soil be poor in any 
one of these plant foods the deficiency must be made 
good by the use of fertilizers. Fertilizers containing 
available nitrogen, phosphoric acid, and potash com- 
]iounds are usually found of benefit to the cereal crops. 
The proper amounts and proportions of these three 
different substances depend on sucli a variety of cir- 
cumstances that no rules for their use can be stated 
here. • 

While corn is classed as a cereal crop, it differs some- 
what in its habits of growth from the small grains. 
Corn is planted in rows some distance apart, and the 
crop rc(|uires thorough but shallow cultivation during 
its period of growth. The small grain crops require 
no cultivation. Corn can draw much of its food from 



160 ELEMENTS OF AGRICULTURE 

the decaying organic matter in the soil, and in conse- 
quence stable manure is specially valuable as a manure 
for this crop. 

149. Fodder Crops. — Instead of gathering the seed 
for food, the entire crop may be harvested and fed to 
animals. Crops harvested in this way make what is 
known as fodder. The crop may be gathered before 
it ripens, and may be fed at once, when it is known as 
GREEN fodder; or it may be dried and made into 
DRY fodder. The most important fodder crops are 
corn and oats. Thus corn and oats are important both 
as cereal and fodder crops. 

150. Green Fodder. — When crops are cut before they 
ripen and are at once fed to cattle the process is known 
as SOILING. Any crop fit for cattle food may be used 
for this purpose — corn, oats, rye, clover, cowpeas, etc. 
It would require too mucli space to describe the many 
advantages claimed by its advocates for this method 
of feeding cattle; suffice it to say, the method is grow- 
ing in favor, and when pasturage is scanty may be 
advantageously practiced. 

151. Ensilage or Silage. — Another method of feeding 
green fodder is to preserve it as ensilage and feed it to 
stock during the winter months. Ensilage is made by 
packing away green fodder in buildings or compart- 
ments called silos, which are large pits dug in the 
ground, or air-tight rooms built above ground. The 
silo most generally used now is built above ground in 
the shape of an immense barrel. A round silo is shown 
in the cut of the model barn. (See frontispiece.) The 
best constructed silos have double walls, between wdiich 
are layers of paper. The size of the silo is, of course^ 



CEREAL AND FODDER CROPS 161 

regulated by the amount of ensilage to be stored away. 
Before the fodder is put into the silo it shovdd be cut 
up^ as in this way a much greater quantity can be stored, 
and the air more thoroughly excluded. Almost any 
of the green crops may be used to make ensilage, but 
corn fodder cut green has been found to be the best 
crop for the pur])ose. The crop is best cut after the 
ears of corn have formed, but before the grains have 
become hard. If the crop is cut too early the ensilage 
is apt to become too acid or sour, and if cut when the 
crop is mature it is somewhat hard and dry. 

Just how the ensilage is preserved in the silo is not 
thoroughly understood, but the simplest explanation 
is as follows: When the ensilage is first stored in the 
silo it begins to heat, and the whole mass in a com- 
j^aratively short time becomes thoroughly warm. Heat- 
ing always takes place when freshly cut green fodder 
of any kind is heaped together. Some of the countless 
bacteria that are present in the air or in the plants 
themselves are inevitably packed away with the ensi- 
lage, and Avhen the ma&s begins to heat they begin to 
work, causing fermentation, the 'first step towards 
decay. These bacteria are supplied with oxygen by the 
air that fills the spaces in the mass of ensilage. But the 
heat generated expands this air and causes much of it 
to escape through the top of the mass. The ensilage 
settles and more air is driven out. Between the loss 
of escaping air and that used up by the bacteria them- 
selves, the supply is soon exhausted, and owing to a lack 
of oxygen the bacteria cease to work and the ensilage 
is preserved from further decay. The mass of ensilage 
11 



162 ELEMENTS OF AGRICULTURE 

soon settleS;, becoming so tightly packed that little or 
no air can enter. The top of the silo, except for a 
covering from the rain, may be kept open to the air, 
and no harm will result. The first few inches of ensi- 
lage which are exposed to the air will rot, bnt the 
ensilage will be found perfectly preserved below. A 
covering of straw helps to preserve the top layer of 
ensilage. The slight fermentation that has taken place 
in the ensilage, it is claimed, improves it as a food for 
stock; but whether this is true or not, ensilage is much 
enjoyed as a food by all classes of stock. 

Ensilage is very valuable as a stock food because it 
furnishes a supply of fresh food at a season when green 
food is unobtainable. It is also a very economical way 
to preserve food, for by this process great quantities of 
food may be stored in a very small space. The feeding 
of ensilage during the winter months is beneficial to 
the health of animals. While ensilage furnishes a 
valuable food for all classes of stock, it is especially 
valuable for milch cows. Feeding ensilage to milch 
cows causes the animals to give a greater supply of 
milk, and at the same time keeps them in better health. 

We learn from Roman writers that the practice of 
preserving fodder as ensilage is a very old one. It is 
probable that the process was known to them hun- 
dreds of years before the birth of Christ. In this 
country ensilage is a comparatively new thing, the 
practice having been begun about 1875, and was based 
upon the method then in vogue in France. It rapidly 
grew in favor until now a silo is part of the equipment 
of every first-class farm where stock is kept. The 



CEREAL AND FODDER CROPS 163 

earlier silos were merely pits dug in the ground, some 
of them lined with cement; but it was troublesome to 
dig the ensilage from these pits, and to avoid this the 
silo built above ground came into use. The modern 
silo is usually built as a part of the feeding barn, and 
on a level with the feeding floor. It should always be 
situated as close as possible to the feeding stalls on 
account of the labor of handling the ensilage; for it is 
both heavy and bulky, and to carry it by hand for long 
distances adds materially to its cost. 

Questions 

1. Name the three most important cereal crops of this 
country. 2. What part of the crop is of most value? 3. In 
what parts of the earth are corn, wheat, and oats grown? 
4. How have the many different soils and climates affected 
these, crops? 5. What sort of roots have the cereals? 
6. Name two regions especially noted for their production 
of grain. 7. What is meant by fodder? 8. What is the 
difference between green and dry fodder? 9. What is feed- 
ing green fodder called? 10. What is ensilage? 11. What 
is a silo? 12. How should the crop be prepared for storage 
in the silo? 13. Why should fodder be cut up before storing 
for ensilage? 14. What happens to the fodder when it is 
first stored in the silo? 15. How is the fermentation of the 
ensilage stopped? 16. Give some reasons why ensilage is 
of value as a stock food. 17. About how old is the practice 
of making ensilage? 18. About what year was ensilage first 
made in this country? 



164 



ELEMENTS OF AGKICULTURE 



CHAPTER XXX.— Fodder Crops and Pastures 

152. Dry Fodder or Forag-e. — Dry fodder may be 
divided into three classes: Dry coarse fodder, 
STRAW, and hay. 

153. Dry Coarse Fodder. — After the corn crop has 
been cut and the ears gathered, the stalk, leaves, and 
shucks form what is generally known as corn fodder; 
a better name for it is corn stover, to distinguish it 
from another kind of corn fodder. When corn is 
planted thick like wheat or oats, the plants make a 
fine growth, but the ears do not develop as well as when 
the crop is planted with greater space between the 
plants. Corn for fodder is planted thick like wheat, 
and the crop is cut before the ears are fully ripe; it 
then makes the true corn fodder. Corn fodder is made 
from the whole plant, ears included; it is the hay of the 
corn plant. Corn stover is made from the plant, with- 
out the ears; it is the straw of the corn plant. Some- 
times the ripened leaves only are gathered for fodder; 
they make what is known as pulled fodder or 
BLADES. Oats, millet, and sorghum are all extensively 
used for making fodder. 

154. Straw. — Straw is that part of the cereal crop 
which remains after the seed has been gathered. From 
the corn crop it is known as stover, but from wheat, 
oats, rice, rye, barley, etc., it is known as straw. 

Straw is not of great value as a stock food. The 



FODDER CROPS AND PASTURES 165 

seed which have been gathered take away most of the 
valuable food compounds, leaving the straw dry and 
hard. Straw can, however, be used to advantage as a 
food, as will be explained later, and is also valuable as 
a bedding for stock. Old or rotting straw forms a 
valuable mulch for poor soils. 

155. Hay. — When grasses, clovers and similar crops 
are cut green and dried in the sun they form what we 
call HAY. The hays formed by coarser grasses such 
as corn and sorghum are called fodder, though they are 
nothing more than hays. Hay differs from the original 
green fodder in having lost nearly all of its moisture. 
Hay, though apparently perfectly dry, contains on an 
average about 10 per cent of moisture. Of course there 
are many kinds of hay resulting from the many kinds 
of forage plants, but we may divide hays into two 
distinct classes, namely, the hay of grasses and the 
hay of legumes. 

156. Hay of Grasses. — There are many kinds of 
grasses that may be grown for hay — grasses suitable to 
different soils and climates. Among the best known hay 
grasses are timothy, orchard grass, bluegrass, meadow 
grasses, and, in the South, Bermuda grass. Two or 
more kinds of grasses may be grown together, and 
clover is often mixed with them. The hay from such 
a mixture is called hay of mixed grasses. Most of 
the grasses grown for hay are perennials; each year 
the top dies to the surface soil, but the next spring a 
fresh growth is sent up by the roots. The grasses 
grown for hay have much the same kind of roots as the 
cereal crops and require for their production much the 



166 ELEMENTS OF AGRICULTURE 

same kinds of soils and fertilizers. Fertilizers contain- 
ing nitrogen often improve crops of grass. Grass crops 
are often grown immediately succeeding crops of wheat 
or oats. The soil is or should be already well prepared 
for the wheat or oats^ and the dense growth of these 
crops checks the growth of weeds, leaving the soil in 
good condition for grass. 

Grass that is mown for hay should not be exposed 
to the sun for days after being cut. The object in 
curing hay is merely to remove a part of the water 
contained in the fresh grass. This is accomplished 
by a few hours' exposure to the sun. The hay should 
then be put into small heaps called cocks; after stand- 
ing in them for a short time the hay should be stored 
away in barns or stacks. It is a great mistake to allow 
cut hay to lie on the ground for days, or even to allow 
it to remain for any length of time in cocks. Through 
the action of the sun and w^eather the quality of the 
hay is much injured. The grass after being cut dries 
out very fast, and the entire process of curing and 
storing hay should not exceed two days. 

Grasses should generally be cut for hay when in full 
bloom or just passing out of bloom, as at this time the 
protein and carbohydrates are more uniformly dis- 
tributed throughout the plant. 

157. Hay of Legumes. — Of the plants belonging to 
the legumes, there are a number that may be used for 
hay. There are several kinds of clover, a number of 
kinds of field peas or beans, some of which are known 
under the name of cowpea. Then there is another kind 
of pea called vetch, and a plant of the same order 



FODDER CROPS AND PASTURES 167 

known as lucerne. There are still other kinds of 
legumes used for hay, but the two first mentioned, the 
clover and cowpea, are more generally used in this 
country than any other. 

The leguminous crops used for hay grow in almost 
all soils and in many climates. Some, however, do best 
in one kind of soil and climate, while other varieties 
prefer very different conditions. Clover does not do 
well in hot climates, nor does it produce profitable 
crops from poor sandy soils; this crop prefers a good 
strong soil well supplied with moisture, lime, and pot- 
ash. The cowpea, on the other hand, does not mature 
in cold climates, and flourishes best under the hot 
southern sun. It will make a good crop on soils too 
poor to produce clover. Light sandy loams, if well 
supplied with moisture and mineral plant food, will 
produce large crops of cowpeas. 

All the crops belonging to the pea family have, as 
you no doubt remember, the power of using the nitro- 
gen of the air for food. They can therefore grow 
well in soils containing little nitrogen. 

These crops are provided with very deep-growing 
roots which spread to a considerable depth through 
the subsoil, from which they draw much plant food. 
The legumes have the power of extracting more food 
from the soil than either the cereal crops or grasses, 
and their deep-growing roots enable them better to 
withstand drought. These crops improve the condition 
of the soil by adding to its store of plant food, and 
also make a very valuable hay which is much used as 
cattle food. The cowpea has been called the "poor 



168 ELEMENTS OF AGEICULTUEE 

man's bank^'; it might more properly have been called 
"the poor soiFs bank/' for from it the poor soil draws 
fresh supplies of plant food. 

Among the legumes are included annuals, biennials, 
and jDerennials. The variety of clover usually grown 
for ha}', known as red clover, is in temperate regions 
a biennial. White clover, the small clover which grows 
in most pastures, is a perennial; and there is still 
another kind, known as crimson clover, which is an 
annual. 

Clover should be cut for hay when in full bloom; 
the peas and beans should be cut wdien the pods are 
formed, but before they become hard. If these crops 
are allowed to become too old before cutting, the leaves 
are liable to drop from the stem, and the value of the 
hay is thereby decreased. 

After being cut, leguminous crops should be cured 
rapidly, for if they are allowed to remain in the sun 
for many hours they become hard and brittle so that 
when handled the leaves drop away from the stem. 

158. Pastures. — A pasture is a field planted in any 
crop on which animals are allowed to graze. Pastures 
are of two kinds, permanent and temporary. 

159. Permanent Pastures. — Fields on which peren- 
nial forage crops are planted and allowed to grow year 
after year are called permanent pastures. The best 
kinds of pasture grasses form a very thick, dense growth 
on the surface of the soil, while below the surface their 
roots are so matted together that sections of a square 
foot or more may be lifted from the soil. Such a growth 
forms what is known as turf or sod. A good turf 



FODDER CROPS AND PASTURES 169 

forms a perfect covering for the soil and protects it 
from surface evaporation, and from the leaching and 
washing of rains. All grasses will not make good turf; 
in fact there are comparatively few varieties that form 
a perfectly even turf suitable for a lawn. On pasture 
lands, however, while a good turf is an advantage it is 
not a necessity; any perennial crop that will cover the 
surface of the soil and furnish food for stock may be 
used. On many soils it is impossible except at great 
cost to establish a good turf, but there are few soils 
on which some sort of a pasture cannot be established. 
Old fields that are now given over to weeds and gullies 
ma}^ with proper care, be converted into excellent pas- 
tures. Only perennial plants should be used to form 
a permanent pasture; annuals and biennials should be 
avoided. There are many perennial plants suitable for 
permanent pastures, but it would require too much 
space to attempt a list of them in this little book. The 
various plants best suited to different soils and climates 
can be determined only by actual test. The United 
States Government has established a number of grass 
gardens for the purpose of determining the most 
valuable forage plants for different soils and climates. 
There are a number of such gardens scattered about in 
this country, and from them we may learn much in 
regard to the various kinds of forage plants. 

160. Temporary Pastures. — When a field is planted 
in some crop to furnish grazing for only a limited time, 
six months or a year for instance, it is called a tem- 
porary pasture. For such pastures almost any forage 



170 ELEMENTS OF AGEICULTUEE 

crop may be used; annuals or biennials serve the pur- 
pose as well as perennials. 

The growing of pasture crops is the least exhausting 
method of cultivating soils. In the first place, all the 
manure from the grazing animals goes directly back 
to the soil. In the second place, the soil is well pro- 
tected from washing, leaching, and surface evaporation. 
The only plant food lost to the soil is that which goes 
to build up the bodies of the pastured animals. There 
are fields known to have been used continuously for 
pasture for on« hundred years or more that are to-day 
as good as ever. 

Pastures should never be allowed to grow up in weeds. 
The weeds should be kept down by cutting before they 
ripen seed; or, if they become too numerous, the field 
should be plowed and planted for a time in some culti- 
vated crop such as corn or tobacco. 

Questions 

1. Into what three classes can dry fodders be divided? 
2. What is corn stover? 3. What is pulled fodder? 4. What 
is corn fodder? 5. What is the difference between corn 
stover and corn fodder? 6. What is straw? 7. For what 
is straw useful? 8. What is hay? 9. How does hay differ 
from the original green forage? 10. What per cent of 
moisture does average hay contain? 11. Name the two 
classes into which hays are divided. 12. Name a few of the 
best grasses for hay. 13. For how many years do most of 
the grasses used for hay live? 14. What leguminous crops 
are grown for hay? 15. How do the roots of legumes differ 
from those of the cereals and grasses? 16. Why are they 
better able to stand dry weather than the grasses? 
17. Why is the cowpea a good crop for poor soils? 18. What 



FODDER CROPS AND PASTURES l7l 

is meant by a pasture? 19. What is permanent pasture? 
20. What sort of crops must be planted to form a perma- 
nent pasture? 21. What is meant by a turf? 22. How does 
turf protect the soil? 23. What is meant by a grass garden? 
24. What is a temporary pasture? 25. Why does not 
pasturing exhaust the soil? 



172 ELEMENTS OF AGKICULTUilE 



CHAPTER XXXI.— Root and Tuber Crops: 
Miscellaneous Crops 

161. Root Crops. — The roots of several different kinda 
of crops furnish valuable food for animals. Turnips, 
beets, and carrots are all grown to feed animals; and 
as they develop late in the fall, they furnish fresh food 
during the winter months, when other fresh food is 
scarce. Radishes, parsnips and salsify are much grown 
in gardens, but are not used as food for stock. All of 
these root crops are biennials, and their large roots 
serve mainly as a storehouse from which the plant 
draws its seed-forming materials during the second 
season's growth. Root crops require great quantities 
of water for their growth; and for their proper develop- 
ment need a well cultivated, deep, loamy soil in which 
the soft roots may expand and reach their full size. 
The fresh leaves and tops of root crops contain large 
amounts of mineral matter which the plant has stored 
up to aid in formin.2: seed the second season. For this 
reason the leaves and tops should always be returned 
to the soil; if they are not returned much valuable 
plant food is lost. 

The soil in which root crops are growing should be 
kept free from weeds, and must be well supplied with 
available nlant food, especially with phosphates. 

162. Tuber Crops. — The two important tuber crops 
are the sweet and the Irish potato. The sweet potato is 
really a root crop, but instead of having one enlarged 



EOOT AND TUBER CROPS, ETC. 



173 



taproot it has clustered roots which are enlarged. The 
enlarged portions of the roots are called tuberous 
roots. Fig. 6 (page 40) shows the enlarged roots of 
the sweet potato. The enlarged portions are provided 
with small rootlets which draw food from the soil. 
The tubers of the Irish potato, on the other hand, are 
not true roots; they are the 
enlarged parts of under- 
ground stems. Fig. 23 
shows the tuber of the Irish 
230tato, and you will notice 
that the tubers, unlike the 
tuberous roots of the sweet 
potato, have no rootlets. 
Both of these crops are per- 
ennials; but since they are 
grown for their tubers a 
fresh crop must be planted 
each year, and as cultivated 
crops they are practically 
annuals. Sweet 2^o^^^c>es 
are sometimes grown for ing from photograph.) 
cattle food, but Irish potatoes are used almost exclu- 
sively for human food. The soil best suited to the 
sweet potato is a warm, well-drained, sandy loam. 
This crop will not do well in a heavy or wet soil. The 
Irish potato requires for its best development richer 
soil than the sweet potato. For both crops the soil 
must be well drained and cultivated, and well supplied 
with moisture, though not wet. The sweet potato does 
best in a temperate or warm climate, and makes but 




Fig. 23.— Tubers and roots of 
the Irish potato. (Original draw- 



ITtt ELEMENTS OF AGRICULTURE 

a poor growth in a cold one. The Irish potato, on the 
other hand, does best in a cold climate, though it will 
grow well in the far South. 

163. Tobacco. — Of the many crops grown on the 
farm besides those already described, we have space 
here to mention only a few, and among these tobacco 
is one of the more important. 

Tobacco, which is an annual, can be grown in Xorth 
America all the way from the equator to the southern 
part of Canada, and in many kinds of soil. This great 
diversity of soil and climate produces a number of 
varieties of tobacco, though the soil seems to have more 
influence on the variety of tobacco than the climate. 
Light sandy soils, as a rule, produce a small bright- 
colored leaf that is much esteemed for smoking tobacco. 
The heavier clay soils produce a large and darker leaf 
which is used for chewing tobacco and snuff. To pro- 
duce a successful crop of tobacco the soil must be 
thoroughly cultivated and kept free from weeds, and the 
crop must be well su])plied with available plant food. 
Because of the large amount of plant food it contains, 
and the clean method of cultivation necessary, tobacco 
is an exhausting crop to the soil. It should not be 
grown year after year on the same soil, but should be 
rotated with other crops, as will be described in the 
next chapter. 

164. Cotton. — This is a distinctly Southern crop and 
cannot be grown profitably north of the southern 
parts of Virginia and Kentucky. Cotton is a very 
exhausting crop on the soil because of the way 
it is cultivated, and because, after the crop is gath- 



KOOT AXD TUBER CROPS, ETC. lY5 

ered, the soil is left bare to the action of the 
weather. When the cottonseed or an equivalent 
amount of cottonseed-meal is returned to the soil as 
manure, the crop itself does not rapidly exhaust the 
suppl}' of plant food in the soil. The lint or fibre of 
cotton contains such a small amount of plant food that 
many crops may be removed from the soil before it 
becomes exhausted. Cotton lint is almost pure cel- 
lulose, and contains very little ash. Three hundred 
pounds of lint cotton, considered a fair crop to the 
acre, contain about 1 pound of nitrogen, ^ pound of 
phosphoric acid, and 2i pounds of potash. If the 
cotton crop removed plant food at this rate it would 
take a long time to impoverish a soil. But 300 pounds 
of lint take along with them 650 pounds of seed which 
contain about 20 pounds of nitrogen, 6| pounds of 
phosphoric acid, and 7| pounds of potash. The lint 
and seed together remove from the soil considerable 
amounts of plant food which must be replaced else the 
soil will become poor. Cotton lands are much exposed 
to the weather during the winter months, and it is 
from this exposure rather than from any demands of 
the crop that they become exhausted. Land should 
not be cropped continuously in cotton year after year, 
but several crops should be rotated. 

165. Garden and Fruit Crops. — These crops are of 
such great variety, and grow in so many different soils 
and climates that it would require too much space 
even to attempt to name the best known varieties of 
either fruits or vegetables. 

As a rule garden and small fruit crops require warm, 



176 ELEMENTS OF AGEICULTUEE 

rich soils well supplied with organic matter^, wood's 

mold being frequently used for .the purpose. Warm 

soils enable the crops to get an early start in the 
spring and so produce an early harvest. 

Questions 

1. Name three root crops grown for stock food. 2. Name 
three other root crops grown for vegetables. 3. Are these 
crops annuals, biennials or perennials? 4. How does the 
enlarged root benefit the growth of the plant? 5. What 
kind of soil do root crops require? 6. What kind of matter 
do the leaves and tops of these plants contain? 7. Name 
the two most important tuber crops. 8. Describe the roots 
of the sweet potato. 9. How do they differ from the 
root crops already mentioned? 10. What are the tubers of 
the Irish potato? 11. Are these crops annuals, biennials or 
perennials? 12. What kind of soil is best adapted to the 
sweet potato? 13. May good crops of either sweet or Irish 
potatoes be grown in a wet soil? 14. In what parts of this 
country does tobacco grow? 1.5. How are the different 
varieties of tobacco produced? 16. Why does the tobacco 
crop exhaust the soil? 17. In what part of the country does 
cotton grow? 18. Why is it that cotton lands soon become 
exhausted? 19. What kinds of soil are best suited for 
garden crops and small fruit? 



EOTATIOX OF CROPS 177 



CHAPTER XXXII.— Rotation of Crops 

166. What is Meant by Rotation. — Rotation means 
changing annually the kind of crop grown npon a 
given soil, the change being usuall}' made in a regular 
order. For instance^ from a certain field a crop of 
tobacco is grown; the next season the same field is 
planted in wheat, and the next in clover; the year after 
the clover, tobacco may be again grown, then wheat, 
and after the wheat clover again. Thus a' rotation of 
these crops is practiced, but four or even more crops 
may be used in a rotation. In general farming rota- 
tion is much practiced, but in special farming it is 
unfortunately seldom used. 

167. Benefits of Rotation. — Rotation of crops when 
properly practiced may be of benefit to the soil in 
many ways: 

1. The way in which soils are cultivated varies with 
different crops. Tobacco and cotton for instance leave 
the soil quite bare; wheat and oats leave a thick stubble 
and large crops of weeds spring up as soon as they are 
gathered. If tobacco or cotton be grown continuously 
on one field, the soil suffers from washing and leach- 
ing. Tobacco and cotton should be rotated with crops 
that protect the soil, such as wheat and oats. 

2. Many crops have shallow roots which draw most 
of their food from the upper soil. If such crops are 
grown continuously on a field, the upper soil becomes 
exhausted while the lower soil is untouched. Crops 

12 



178 



ELEMENTS OF AGRICULTUEE 



with shallow growing roots should be rotated with 
crops that have deep roots. Deep-growing roots draw 
much food from the subsoil. 

3. Some crops require specially large amounts of 
some particular plant food. Thus tobacco requires 
about ten times as much potash as phosphoric acid, 
and if such a crop be grown continuously upon a soil 
the potash becomes exhausted before the phosphoric 
acid. Tobacco should be rotated with some crop that 
requires large amounts of phosphates — wheat, for in- 
stance. 

4. From the growth of some crops the soil becomes 
infested with weeds. Thus daises or wild carrots may 
become very numerous in a pasture or hayfield. When 
weeds become too numerous the field should be planted 
in some cleanly cultivated crop, such as corn, tobacco, 
or cotton. 

5. Many crops have special insect enemies that feed 
upon them. Thus tobacco has the tobacco worm, 
wheat the Hessian fly, potatoes the potato beetle, and 
almost every crop grown has its special enemies among 
the thousands of insects found on the farm. If the 
same crop be grown upon a field year after year, these 
insect enemies increase, for they are supplied with just 
the food they require. If, however, the kind of crop 
be changed, the insects suffer. A tobacco worm hatched 
in a wheat field finds nothing to feed on, and a potato 
beetle starves in a tobacco patch. 

G. Most crops are subject to attacks of some special 
disease which may not affect other crops. Wheat 
suffers from a disease called rust, but tobacco is not 



EOTATIOX OF CROPS 179 

affected by it. Corn suffers from smut, bu,t tobacco 
does not. These plant diseases spread much as diseases 
spread among human beings and animals. Thus per- 
sons occupying a room previously occupied by a man 
suffering with a contagious disease like smallpox or 
scarlet fever are liable to contract the disease. The 
room is said to be infected by the disease, and in a 
similar way soils become infected by plant diseases. 
Wheat, for instance, when grown on a soil which tlie 
year before produced a crop of wheat affected by rust, 
is liable to contract the disease. But if some other 
crop is planted which is not liable to this disease there 
is no danger. A proper rotation of crops, for the rea- 
sons stated, checks the spread of plant diseases. 

168. Examples of Rotation. — The crops used in rota- 
tion must, of course, be determined by the kind of 
crops it is desired to grow. The following examples 
have been found satisfactory: 

Eotation 1. — First year tobacco, second year wheat, 
third year wheat, fourth and fifth years clover. 

Eotation 2. — First year corn, second year oats, third 
year wheat, fourth and fifth years clover. 

Rotation 3. — First year tobacco, second year wheat, 
third and fourth years clover. 

Eotation 4. — First year corn, second 3'ear wheat, 
third and fourth years clover. 

Eotation 5. — First year cotton, second year wheat, 
third and fourth years clover. 

In rotations cowpeas or any other suitable legumi- 
nous crop may be used in place of clover. 



180 



ELEMENTS OF AGRICULTIJRE 



This simple diagram serves to illustrate a common 
rotation which is usually called the four-shift system: 



First 
Field. 



Second 
Field. 



Third 
Field. 



Fourth 
Field. 



First year. . . 
Second year . 
Third year. . 
Fourth year 



Corn. 
Wheat. 

Clover. 
Clover. 



Wheat. 
Clover. 
Clover. 
Corn. 



Clover. 
Clover. 
Corn. 
Wheat. 



Clover. 
Corn. 
Wheat. 
Clover. 



Questions 

1. What is meant by a rotation of crops? 2. Give an ex- 
ample of rotation. 3. In what kind of farming is rotation 
of crops much practiced? 4. Clean cultivation exposes the 
soil to what danger? 5. How does rotation lessen the 
danger arising from clean cultivation? 6. Why is it best 
to grew a crop with deep-growing roots after a crop with 
shallow roots? 7. When one crop is grown continuously, 
is the drain upon the soil's supply of plant food uniform? 
8. How is this irregularity corrected by rotation? 9. How 
does rotation check the spread of weeds? 10. How does 
rotation check the spread of injurious insects? How does 
rotation check plant diseases? 11. Is rotation of crops prac- 
ticed in your neighborhood? 12. Give a few examples of 
rotation. 

PROBLEM 



Make a diagram showing a five-shift rotation consisting 
of corn, oats, wheat, and two years clover. 



COMPOSITION OF ANIMALS 181 



PART VI.— Animal Peodxjction 



CHAPTER XXXIII.— Composition of Animals 

169. Stock Fanning. — Farm crops are either sold 
direct from the farm^ or else turned into animals or 
animal products, which are sold. The latter practice 
is called stock farming, only such crops being grown 
as are needed to feed the animals. This is the highest 
order of farming, as it requires not only a knowledge 
of how to grow crops, but of how to breed and feed 
animals. The stock farmer is both a grower of crops 
and a manufacturer of flesh. There are many kinds 
of stock farms; for instance there are cattle farms, 
sheep farms, goat farms, horse farms, poultry farms, 
and dairy farms, all run for the production of animals. 
Almost every farmer is more or less a stock raiser, for 
some animals must be kept on every farm to help with 
the farm work. It is important that all farmers should 
know how to feed and care for animals, and for stock 
farmers such knowledge is absolutely necessary. In 
order to feed animals to the best advantage it is well 
to know something of the animal's body and how it 
is built up. 

170. Composition of Animal Bodies. — Bones and flesh 
make up a large part of the bodies of animals; the 
bones serve as a sort of framework which the flesh 
binds together. Through the flesh run the nerves and 
blood vessels — veins and arteries; and, protected by the 



182 . ELEMENTS OF AGRICTJLTUKE 

flesh and bones, are found the vital organs — the brain, 
the heart, lungs, digestive organs, etc. Covering the 
body is the skin, which is in turn often covered by hair 
or feathers. The limbs are provided with hoofs or 
claws, and from the heads of many animals grow horns. 
These various parts of the animal bodies, which are so 
difl'erent in appearance, are quite different in composi- 
tion, though they all contain certain substances in 
common. 

171. Moisture. — All parts of the animal body con- 
tain moisture; even the apparently dry bones contain 
some moisture, and some parts of the body contain 
large quantities of water. Young animals, like young 
plants, contain more moisture than they do when they 
grow older. When the flesh of animals is dried out it 
forms cured meat. Most of us are familiar with the 
dried beef which is sold on the market as "chip-beef." 
This process of curing meat is similar to curing grass 
for hay; in both cases most of the moisture is driven 
off. The flesh of most animals usually contains from 
40 to 60 per cent of water, seldom more than 60 per 
cent. The bones of course contain less moisture than 
the flesh, and the blood contains much more. The 
bodies of most domestic animals contain about 50 per 
cent of water, not counting the contents of the stomach. 
That part of the animal body which remains after the 
water is driven off is called dry matter. 

172. Dry Matter. — When the dry matter of animal 
bodies is burned the greater part disappears into the 
air as gas and smoke, leaving behind a small quantity 
ol ash. The part disappearing into the air is called 



COMPOSITION' OF AXIMALS 183 

organic matter or volatile matter, and the part remain- 
ing as ash is called inorganic matter, mineral matter, or 
ash. 

173. Organic Matter. — The organic, or volatile 
matter, of animal bodies may be divided into two 
classes of compounds, one class containing nitrogen, 
and the other containing no nitrogen. Just as in the 
case of plants, the. nitrogen-containing compounds are 
called protein, and the compounds containing no nitro- 
gen are called non-nitrogenous substances. These com- 
pounds are, however, quite different in appearance from 
those found in plants, though they are made up of the 
same elements. The relative proportions of these two 
classes of substances are quite different in animal 
bodies from what they are in plants. In nearly all 
plants there are more of non-nitrogenous compounds 
than of nitrogenous; but in animals the reverse is true. 
The animal body contains as a rule more nitrogenous 
substances than non-nitrogenous. 

174. Nitrogenous Substances: Protein. — The dry 
matter of the muscles, nerves, and tendons of animal 
bodies is made up almost entirely of nitrogen com- 
pounds. The hoofs, horns, claws, skin, blood, hair, 
and bones contain considerable amounts of nitrogen. 
The greater part of the bodies of animals is made up 
of compounds of nitrogen, though of course the differ- 
ent parts of the body contain different amounts. The 
bones and skin, for instance, contain less nitrogen than 
the flesh. These nitrogen compounds of animal bodies 
are made up of exactly the same elements that make 
up those of plants; namely, carbon, oxygen, hydrogen, 



184 



ELEMENTS OF AGRICULTURE 



nitrogen, sulphur, and a litttle phosphorus. But 
though they are made up of the same elements, they 
are different compounds, and differ in appearance and 
in the proportions in wliich the elements are comhined. 
The nitrogen compounds are hy far the most important 
compounds of the animal hody. 

175. Non-Nitrogenous Substances. — The non-nitrog- 
enous matter of plants is made up principally of starch, 
sugar, gum, and woody matter, usually with small 
quantities of oil or fat. In animal bodies, on the other 
hand, nearly all of this matter is fat or oil. No starch 
or woody matter is found in animal bodies, and only a 
little sugar. 

The amount of fat in animal bodies varies greatly. 
Different animals contain very different amounts of fat, 
and the same body varies from day to day in the 
amount of fat it contains. The non-nitrogenous mat- 
ter of animal bodies is made up of the same elements 
as the non-nitrogenous matter of plants; namely, car- 
bon, hydrogen, and oxygen. These elements are, how- 
ever, combined in a different way, and the fats of 
animal bodies are different in appearance from the 
fats of plants. Thus lard is quite a different thing 
from cottonseed oil, though they both contain the same 
elements. 

176. Mineral Matter, or Ash. — Most of the mineral 
matter of animal bodies is contained in the bones, and 
only small quantities are found in the flesh and blood. 
Older animals as a rule contain more ash than younger 
animals. This is because their bones are larger and 
better developed. As a large part of the bones of all 



COMPOSITION OF ANIMALS 185 

animals is made up of phosphates, the ash of animal 
bodies consists largely of phosphate. Ash makes up 
about 2 to 5 per cent of animal bodies. The ash of 
animal bodies contains small quantities of most of the 
elements found in the ashes of plants. The phosphates 
make up about 80 per cent of the ash. 

Questions 

1. What is meant by stock farming? 2. Name some of the 
various kinds of stock farms. 3. Name some of the princi- 
pal substances that make up animal bodies. 4, In what does 
the process of curing meat resemble that of curing hay? 
5. As a rule, do animal bodies contain as much moisture 
as plants? 6. What two classes of compounds make up the 
dry matter of animal bodies? 7. Divide the organic matter 
into two classes of substances. 8. What part of the flesh is 
made up largely of protein? 9. In what other parts of the 
body is protein found? 10. As a rule, which contain the 
more protein, animal bodies or plants? 11. What elements 
make up protein? 12. What substance makes up most of the 
non-nitrogenous matter of animal bodies? 13. Is starch or 
woody matter found in animal bodies? 14. In what part of 
animal bodies is most of the mineral matter found? 



186 ELEMENTS OF AGRICULTURE 



CHAPTEE XXXIV.— Food, Work, and Growth 
OF Animals 

177. Animals and Plants are Alike in Composition. — 

In the last chapter we learned that in composition 
animal bodies closely resemble plants. This is not sur- 
prising when we consider the fact that the food of 
animals consists principally of plants. It is true that 
some animals are carnivorous, that is, they live on the 
flesh of other animals, but the animals so used for food 
derive their food from plants. 

178. Plants Manufacture Food for Animals. — While 
plants and animals are much alike in composition they 
differ very much in their manner of taking in food and 
growing. Plants as a rule take up the necessary raw 
materials from the earth and air, and change them 
into the compounds which make up their supply of 
protein, carbohydrates, fats, etc. Animals as a rule 
have not this power of taking the raw materials into 
their bodies and changing them into other compounds. 
A horse or cow will starve on the food that supplies 
plants, even though this food contains all the elements 
found in the animal's body. The raw materials of the 
earth and air must first be made into plants before they 
are fit food for animals. Plants are the makers of 
animal food. 

179. All Living Animals are Constantly Growing. — 
The grow^th of young animals is generally rapid; they 
increase in size till they reach the point where they 



FOOD, WORK, AND GROWTH OF ANIMALS 187 

apparently cease to grow, but in reality they go on 
growing, though their size remains about constant. 
They are continually repairing and rebuilding the worn 
places in their bodies; twice each year a new crop of 
hair is grown, the various muscles are constantly re- 
newed, and in this way the body is continually grow- 
ing. These repairs and changes cease only when the 
animal dies. Life means change and constant repair- 
ing; an addition of new growth and a replacing of old 
parts by new. In plants these changes usually mean 
the addition of new growth, most plants continuing to 
increase in size so long as they live. Most animals, on 
the other hand, reach a fixed point where they cease 
to grow in size, and such changes in the bodies as take 
place consist in renewing worn parts. 

180. Food Necessary for Growth. — To effect the 
changes that are constantly taking place in the animal 
body a constant supply of the proper kinds of food is 
necessary. Xot only is food necessary for the repairs 
that are constantly going on, but it is necessary to keep 
up the temperature of the body. If the temperature 
of an animal's body is much reduced, a chill is the result 
and sickness usually follows. Food and a proper supply 
of fresh air are necessary to prevent the cooling off of 
the animal body. 

181. Food Necessary for Work. — Food and air are 
also necessary to enable the animal to use its muscles 
in moving about. The animal body has often been 
compared to a steam engine. Feed an engine fuel, 
water, and air, and it does work; take away its supply 
of any one of these three things, it ceases to move, and 



188 * ELEMENTS OF AGRICULTURE 

is said to be dead. The animal body requires food, 
water, and air, and when supplied with them it can 
move about and do work. Take away any one of them, 
and the body soon becomes unable to move, and dies. 
182. How to Feed Animals. — The art of feeding 
animals is knowing how to supply them with the proper 
amounts and kinds of food. Different kinds of animals 
of course require different amounts of food. A cow 
or a steer can eat at one time much more food than a 
horse, and a horse can eat more than a sheep. Then, 
too, the same kind of animal under different conditions 
requires different amounts of food. A working horse 
requires more and better food than a horse that is 
doing nothing. A cow giving milk requires more food 
than a dry cow. To grow and feed animals successfully, 
all these things must be considered. In feeding stock 
one thing that should especially be considered is the 
fact that scrubby animals eat just as much as fine, 
well-bred stock, xV cow giving 2 or 3 quarts of milk 
a day will eat just about as much as a cow giving two 
gallons. A cow giving an average of 3 quarts of milk 
a day will produce in six months about 137 gallons, 
which at 20 cents a gallon w^ould be worth just $27.40. 
A cow giving an average of 2 gallons of milk a day will 
produce in the same length of time 365 gallons, which 
at 20 cents would be worth $73.00. The food of each 
is about equal in cost, yet the milk produced by the 
better cow is worth $45.60 more than the milk produced 
by the scrub. The scrub costs as much to feed as the 
good cow and does less than half the work; she is, 
therefore, more than twice as expensive to keep. A 



FOOD, WORK, AND GROWTH OF ANI:MALS 189 

little lialf-gTowii ''"runt" of a horse may eat nearly as 
much as a fine powerful draft horse^ and yet not be 
able to do half the work. It is, therefore, just about 
twice as expensive to keep. The poorer the class of 
stock the more expensive it is to keep. 

Questions 

1. The food of most animals consists of what? 2. How 
do the foods of animals differ from the foods of plants? 
3. How are the raw materials of the earth and air con- 
verted into animal foods? 4. Do living animals ever cease 
to grow? 5. What changes are constantly going on in the 
bodies of animals? 6. To effect the changes in animal 
bodies what is necessary? 7. What is necessary to keep 
up the temperature of animal bodies? 8. What three things 
are necessary to enable an animal to work?* 9. Why is it 
more expensive to keep scrub stock than it is to keep more 
valuable animals? 

PROBLEM 

Let us suppose that we have to feed two milch cows, A 
and B. They both eat about the same amount of food and 
cost the same to keep. A, however, gives an average of 
3 gallons of milk a day, while B gives only an average of 
7 quarts. Milk is worth 20 cents a gallon. What is the ap- 
proximate value of the milk produced in a month of 30 days 
by each cow? 



190 ELEMENTS OF AGIUCULTURE 



CHAPTEE XXXV.— Care of Animals 

183. Care as Important as Feeding. — In the last 
chapter you were told that the art of feeding is know- 
ing how to supj^ly the animal with the proper amounts 
and kinds of food. There are several ways of supply- 
ing the animal with food; it may he turned out to pas- 
ture, or it may he kept in the stable, and the food 
given it, but whatever the method adopted the animal 
should be well treated. If the animal is abused or 
neglected it will suffer, no matter how well the actual 
feeding is done. Good feeding does not consist simply 
in good food; it means good attention and kindness 
as well. If the animal is to be kept in a stable, the 
first care should be to provide a comfortable stable. 

184. Stables. — Children and plants cannot develop 
without fresh air and sunshine; the same is true of 
domestic animals. To keep animals shut up in foul, 
dark, ill-ventilated stables and expect them to grow 
and do well is as foolish as attempting to grow wheat 
in a cellar. Yet how many animals are provided with 
comfortable stables ? Once a year is usually consid- 
ered often enough to clean a stable. The air is nearly 
always saturated with the odor of decaying organic 
matter. The light of day seldom penetrates its foul 
interior, and here the poor animals must spend a large 
part of their lives. Is it any wonder that so many 
cattle suffer from consumption, and through their flesh 
and milk transmit this fatal disease to man ? All ani- 



CARE OF ANIMALS 191 

mals are cleanly in their habits, and there are few 
domestic animals that would of their own accord live 
in the foul stables often provided for their use by 
thoughtless owners. There is a popular belief that a 
man's character may be judged by the way he treats 
his beasts. Let us hope that this is not altogether true, 
for it is terrible to think that the stock owners of this 
country are possessed of characters as foul as the 
stables they provide for their animals. 

All stables should if possible be well lighted and 
ventilated, and should always be kept clean. Each day 
fresh bedding should be provided for the animal, no 
matter whether the old bedding is thrown out or re- 
tained. The floor of the stable should be kept as dry 
as possible. 

185. Kindness to Animals. — Kindness is necessary 
to the successful feeding of domestic animals. Do- 
mestic animals that are well treated are nearly always 
gentle, and easily handled and fed. They enjoy their 
food, and by their improved condition and good be- 
havior more than repay the kindness shown them. On 
the other hand, ill treatment almost invariably causes 
the animals to lose flesh. From blows and abuse they 
become irritable, often vicious, and difficult to manage. 
The nervous worry caused by ill treatment brings on 
indigestion, and loss of flesh results. The man who 
illtreats his animals pays for it out of his own pocket. 
Xot only does he lose the respect of all right-minded 
people, but he actually loses money because of the de- 
crease in value of his stock. It is an invariable rule 
that animals under kind treatment can do more work 



192 ELEMENTS OF AGEICULTTJRE 

than when abused. Systematic beating or abuse de- 
creases the value of an animal many dollars. The 
utterly senseless and cruel practice of using checkreins 
to force horses to hold up their heads in an unnatu- 
ral position cannot be too strongly condemned. The 
checkrein should be banished from all well-regulated 
farms. 

186. Treatment of Cows. — The cow is very sensitive 
to ill treatment. One of the dairy experts of this 
country, after a careful study of milch cows, says: 
"The elaboration [formation] of milk does not pro- 
ceed at a uniform rate from milking to milking, but is 
most active at the time of milking, and is dependent 
not only upon the stimulus which the milk glands derive 
from the manipulation of the teats and udder, but upon 
the nervous condition of the animal at the time of 
milking. 

"In consequence of this, slight changes in the con- 
dition under which the milking is done may have a 
decided influence upon. both the yield and quality of 
the milk.^^ He says further : " It is my opinion that 
kind treatment and pleasant surroundings will have a 
greater influence upon the quality of milk than the 
kind of food, provided the rations given contain suffi- 
cient nutrients for the maintenance of the animal.''* 

187. Regularity and System. — All animals should 
be fed and watered regularly, and it is very important 
that cows should be milked at regular intervals. Most 
animals form habits quickly, and soon learn when to 



Trofessor Babcock in the Wisconsin Station Report for 1889, 



CAKE OF ANIMALS 193 

expect their food and exercise. Changing suddenly the 
time and manner of feeding disturbs the animals, mak- 
ing them restless and uneasy. Changing the time or 
manner of milking often has a bad effect on the quan- 
tity or quality of milk. 

188. Exercise and Air.— All animals confined in 
stables should be given a certain amount of daily exer- 
cise and fresh air. Fattening cattle require but little 
exercise, but they need fresh air and sunshine. Milch 
cows do best when they have a few hours in which to 
walk about and exercise their muscles. Animals con- 
fined in close stalls have little opportunity to keep their 
skins clean by licking themselves. The habit animals 
have of licking their skins is as important to them as 
bathing is to human beings. When they cannot lick 
themselves they suffer as much or more than people 
who have no opportunity of washing their skins. Brush- 
ing the animals each day may partially take the place 
of their licking. 

189. Exposure to the Weather. — Many persons ap- 
pear to have the idea that domestic animals can endure 
without injury any amount of exposure to the weather. 
Horses that have become very warm from inuch exer- 
cise are left to cool off in the coldest weather with no 
more protection than their own moist skins. Cattle 
of all kinds and ages are left out to face the coldest 
blizzards, or are kept in draughty stables. Many ani- 
mals can endure exposure of this kind, just as some 
persons of strong constitution can survive exposure 
that would kill most people, but the number of animals 
that die each year from exposure to the weather is 

13 



194 ELEMENTS OF AGRICULTUKE 

very large, and many, while not killed outright, are 
much weakened and thus made liable to disease. To 
obtain the best results from feeding, the animal must 
be provided with some protection from the extremes 
of heat and cold. 

Questions 

1. In what does the art of feeding consist? 2. What is 
necessary besides good food to secure success in feeding 
animals? 3. In what kind of stables should animals be 
kept? 4. Why? 5. What effect does kind treatment have 
on most animals? 6. What effect does abuse have on the 
value of an animal? 7. How does the treatment of the cow 
affect the amount and quality of the milk? 8. Why is it 
best to feed and attend animals with regularity and system? 
9. What is a cow's substitute for a bath? 10. Why should 
animals be protected from the weather? 



FEEDING OF ANIMALS 195 



CHAPTER XXXVI.— Feeding of Animals 

190. Methods of Feeding. — As already stated, there 
are several methods of feeding domestic animals. The 
animal may be turned out to find its own living from 
the plants growing naturally in the soil. This method 
of feeding is known as pasturing. Sometimes the 
animals turned out to pasture are supplied in winter 
or in very dry weather with extra amounts of food in 
the shape of hay, straw, grain, etc. Another method 
of feeding is to keep the animals in a stable and supply 
them food at regular intervals; this is known as stall- 
feeding, and is much practiced. The art of feeding 
has to do mainly with stall-feeding, for when the 
animal is at pasture it, as a rule, finds its own food. 
Now, in either method of feeding, the first thing to 
be looked after is water. 

191. Water for Animals. — Domestic animals should 
always be furnished an abundant supply of fresh, 
pure water. Most farms are well supplied with good 
water, but, unfortunately, the supply provided for 
animals is not always good. The stagnant water of 
ponds, and the water of polluted streams is often con- 
sidered good enough for their use. All domestic 
animals prefer pure water, and if they drink dirty water 
it is only because they can get no better. Impure water 
is often the beginning of disease in animals, and from 
them it may pass to human beings. The milk from 
cows supplied with impure water often causes outbreaks 



196 



ELEMENTS OF AGRICULTURE 



of disease among human beings. The dair3^man cannot 
be too careful about the water he provides for his cows. 

192. Pasturing. — Herbivorous or plant-eating ani- 
mals in their native state make their living off the 
plants growing naturall}^ in the soil, and many domestic 
animals are fed in this wa}'. For a part of the year 
at least they are turned out to find their own living 
from the grass and other plants which form their food. 
This is the method generally practiced for raising 
animals that are to serve as food for man. In raising 
cattle for market, the object is to produce the greatest 
weight of flesh at the least possible cost. Where -the 
soil w411 grow^ grasses suitable for pasture, large tracts 
of land are planted in grass, which furnishes a good 
living to the cattle grazing it. The labor and cost of 
feeding is in this way greatly reduced, and the profits 
resulting from the sale of the cattle correspondingly 
increased. The bluegrass regions of the Eastern States, 
and the great prairie regions of the West, supply 
pasture for many herds of cattle. Sheep can make their 
living on rougher and poorer fare than cattle, and 
the mountains, Avhile often too poor to support cattle, 
will furnish excellent pasture for sheep. 

Even the best of pastures, however, can supply but 
a scant living for domestic animals in winter, and 
during this season of cold other food in some shape 
should be provided for them. During cold weather 
animals require a constant supply of proper food to 
keep them warm If not fed regularly, their store of 
fat is all used up to maintain the proper body tem- 
perature, and they become thin and weak, and unable 



FEEDING OF ANIMALS 197 

to withstand the attacks of disease. A regular supply 
of food better enables animals to endure the cold and 
withstand sudden changes of temperature. An animal 
irregularly supplied with food is poorly prepared to 
meet the sudden changes in our climate. In a half- 
starved condition it may be subjected to the cold of 
a blizzard, and suffer more in consequence than a well- 
fed animal. To obtain healthy, well-grown animals of 
any kind, a constant supply of good food is necessary. 
Animals may either be left out all the year, and during 
the winter have extra food supplied them, or they may 
be stabled and fed in stalls. If left in the pasture, 
some sort of rough shelter should be provided as a 
protection against the coldest weather. We shall con- 
sider the subject of stall-feeding in the following 
chapters. 

Questions 

1. Name several methods of feeding domestic animals. 
2. Why is it important to supply domestic animals with 
pure water? 3. What constitutes the food of herbivorous 
animals? 4. What is meant by pasturing animals? 5. In 
raising cattle for market what is the prime object? 6. Name 
a part of this country where large herds of cattle are raised. 
7. What class of stock can make their living on a poorer 
pasture than cattle? 8. Why should animals be supplied 
with extra food during the winter? 



198 ELEMENTS OF AGllICULTUKE 



CHAPTER XXXVII.— Stock Food 

193. Need for Fixing the Amounts of Food Supplied 
Animals. — In stall-feeding the animal mnst be sup- 
plied with the proper amounts of food to keep it in 
good condition. How are we to know just how much 
food different animals require to keep them in condi- 
tion ? We may guess at the proper amounts, or we may 
feed the animal till it will eat no more, but both of 
these methods are liable to cause mistakes. Animals 
are greedy, and, if allowed, will often eat more than is 
good for them. So it is best to know just how much 
food to give them. Xow there is a method of deter- 
mining how much food different animals require to 
keep them in condition. Let us see what it is. 

194. Digestion. — Plants from the elements of earth, 
air, and water build up the compounds that go to 
form them. Animals build up their bodies from the 
compounds formed by the plants. The compounds of 
the plants are made over in the animal body into other 
compounds, and the process is called digestion. The 
process of digestion is a very complicated one, and is 
not thoroughly understood; so we need not consider 
it just now. It is enough for our purpose to know 
that animals in building up their bodies use the com- 
pounds formed by plants. These foods are taken into 
the animal's stomach where portions of the different 
compounds are digested, which means that they become 



STOCK FOOD 199 

part of the animars body. The undigested portion is 
passed off as manure. 

195. Protein, Non-Nitrogenous Matter, and Mineral 
Matter All Necessary Foods. — The nitrogen com- 
pounds of animal bodies are built up only from the 
nitrogen compounds of plants. The non-nitrogenous 
matters of animal bodies are built up principally from 
the non-nitrogenous matters of plants, though they 
may also be formed from the nitrogen compounds. 
The mineral matter of animal bodies comes largely 
from the mineral matter of plants. Animals, then, in 
order to keep their bodies built up, must be supplied 
with food containing protein, non-nitrogenous matter, 
and mineral matter. The amount of mineral matter 
required in animal bodies is so small that there is 
always enough in the ordinary supply of food. It is 
not necessary to consider mineral matter as a food. 
Salt is not considered a food, but merely a relish. 
Protein and non-nitrogenous matter are then the only 
solid substances we need consider in selecting food for 
animals. Protein builds up the muscles, nerves, blood, 
bones, and all the nitrogen-containing parts of the 
body. It may also help to form fat and keep the body 
warm. Protein compounds may serve to build up every 
part of the animal bod}^, and animals may live on a 
food made up exclusively of protein. But such a diet is 
hot good for the health of most domestic animals. N'on- 
nitrogenous matters cannot build up the nitrogen com- 
pounds of animal bodies, and animals starve to death on 
a diet of non-nitrogenous matter alone. But certain 
amounts of non-nitroo^enous matters are necessary for 



200 



ELEMENTS OF AGRICULTURE 



the health of the animal, and all animal food should 
contain some of these compounds. 

196. Composition of Foods. — We have already learned 
that plants are made up of water and dr}' matter, and 
that the dry matter is made up of mineral matter, pro- 
tein, and non-nitrogenous matter. In order to deter- 
mine the value of plants for cattle foods, the amounts 
of the different substances tliey contain have been 
determined. In determinino- the amounts of the com- 
pounds, the plant is anal3'zed, which means that it is 
broken up into some of the substances that form it. 
When cattle foods are analyzed, they are divided up 
into six classes of substances as follows: 

1. Water is determined by drying in an oven a 
weighed portion of the finely ground substance until it 
is perfectly dry. The dried portion is then weighed, 
and the loss in weight gives the amount of water, or 
MOISTURE as it is often called. 

2. Ash is determined by burning at a low heat a 
weighed portion of the ground substance. The weight 
of the ashes gives the amount of mineral matter or ash, 
usually called crude ash. 

3. Nitrogen is determined by a process that is too 
complicated for us to describe here, but which is known 
to be accurate. Protein is known to contain about 16 
per cent of nitrogen, so if we multiply the nitrogen 
found by 61 we get the amount of protein in the sub- 
stance. The protein is usually called crude protein. 

4. Fats and oils are dissolved from a weighed por- 



STOCK FOOD 201 

tion of the ground substance by means of ether."^ The 
ether is evaporated, and the fats and oil are weighed. 
The result is usually called crude fat. 

5. The woody matter is determined in a portion of 
the ground substance by dissolving out all the other 
compounds by boiling the sample, first with a solution 
of an acid, and then with an alkali. The woody matter 
is then washed, dried, weighed, burned, and the weight 
of ash subtracted. The result is crude fiber. 

6. The ])eT cent of moisture, crude ash, crude pro- 
tein, crude fat, and crude fiber are all added together 
and the sum subtracted from 100. The remainder 
represents what is called nitrogen-free extract. 
Nitrogen-free extract is so called because it contains 
no nitrogen compounds. It is made up principally of 
starch, sugar, and gum, but includes everything in the 
plant except those substances already determined. 

An analysis made in the manner just described is 
called a proximate analysis of a feeding stuff. It 
is called proximate because all the compounds in the 
substance are not determined, but only those necessary 
to decide its value as a cattle food. The sum of the 
nutrients in a proximate analysis must always make 
100. 

Different cattle foods differ greatly in composition; 
some contain large amounts of protein, others of fat, 
and still others of starch. Even the same food, under 
different conditions, varies in composition. A great 



*Ether is a liquid much used in medicine to produce insensibility to 
pain in operations. 1 1 dissolves fats and oils very easily, and evaporates 
very quickly. 



202 ELEMENTS OF AGRICULTURE 

many analyses have been made of the more important 
feeding stuffs, and the average of all the analyses of 
each food gives its average composition. Nearly 
everything that can be used as a cattle food has been 
analyzed;, and the results recorded. In Table Y of the 
Appendix are arranged the averages of a number of 
analyses of the more important feeding stuffs. These 
figures are intended to show what these different foods 
contain under average conditions. 

197. Nutrients. — The various compounds in plants 
that are useful for building up the animal body are 
called NUTRIENTS, because they nourish the animal 
body. The nutrients of plants are protein, and non- 
nitrogenous matters; the non-nitrogenous matters being 
divided into fat, nitrogen-free extract, and fiber. 

Questions 

1. Why is it best to know exactly how much food stall- 
fed animals require to keep them in good condition? 
2, How do animals build up their bodies? 3. What becomes 
of the food the animal takes into its body in eating? 4. The 
change that food undergoes in the animal's body is called 
what? 5. How are the nitrogen compounds in animal bodies 
built up? 6. How is the non-nitrogenous matter of animal 
bodies built up? 7. Can the non-nitrogenous matters of 
plants build up nitrogen compounds in animal bodies? 
8. Can the nitrogen compounds of plants build up the non- 
nitrogenous matters in animal bodies? 9. What is meant 
by an analysis of a food? 10. How is the amount of water 
determined in a food? 11. How is ash determined? 12. How 
is protein determined from nitrogen? 13. How is fat deter- 
mined? 14. How is woody matter determined? 15. What is 
meant by nitrogen-free extract, and how is it determined? 
16. What is a proximate analysis? 17. What are nutrients? 



STOCK FOOD 203 



PROBLEM 



Suppose a sample of hay contains 9.77 per cent of water, 
8.99 per cent of protein, 1.75 per cent of fat, 31.05 per cent 
of fiber and 4.55 per cent of ash. How much nitrogen-free 
extract does the hay contain? 



204 ELEMENTS OF AGRICULTURE 



CHAPTEE XXXVIII.— Digestibility of Stock 
Foods 

198. The Value of a Food Depends on Its Digesti- 
bility. — Only a part of the food eaten by animals is 
digested; the undigested portion is passed off as manure. 
Naturally, the portion digested is of much greater 
value to the animal body than the undigested portion. 
So in judging of the value of a cattle food, we must 
always take into consideration the digestibility of the 
nutrients contained in the food. Table V of the 
Appendix shows the results of a number of analyses 
of different foods, most of which are very different in 
composition. These foods also- differ very much in 
the amounts of digestible nutrients they contain. Let 
us see how it is possible to determine the digestibility 
of the nutrients of cattle foods. 

199. Digestion Experiment.— Of the food eaten by 
animals, a part is digested and retained in the body, 
and a part passed off as manure. Xow, suppose we 
feed to an animal a weighed portion of food in which 
we have determined accurately the amounts of the 
various nutrients. If no other food has been given the 
animal, we can collect the manure resulting and in it 
determine the amounts of the nutrients undigested. 
The difference between the total nutrients in the food 
and the undigested nutrients in the manure will give 
us the digestible nutrients. Suppose we select an ox 
and feed him 30 pounds of hay per day. The hay con- 



DIGESTIBILITY OF STOCK FOODS 205 

tains G per cent of protein. So we are supplying the 
ox 1.8 pounds of protein per day. If the manure from 
the ox contain 3 per cent of protein, only one-half or 
50 per cent of the protein of the hay is digestible. In 
the same way we may determine the digestibility of the 
other nutrients of the food. Such tests of foods as 
these are called digestion experiments. 

In making digestion experiments much care and 
patience are required. For use in such tests only 
healthy average animals should be selected, and for a 
few days before the beginning of the experiment the 
animal must be fed nothing but the food to be tested. 
In this time the manure resulting from any other food 
eaten previously by the animal is passed from the body. 
Digestion experiments are usually continued for 
several days or even weeks, and during the time they 
are in progress the animal must be carefully looked 
after. Samples of the food to be tested must be care- 
fully analyzed to determine the amounts of its 
nutrients; and at certain intervals the animal must be 
supplied with weighed quantities of the food. All the 
manure, both liquid and solid, passed by the animal 
during the experiment should be collected and weighed. 
Samples of the manure are analyzed in order to deter- 
mine the amounts of the nutrients left in it; a number 
of samples being taken, each at a different stage of the 
experiment. The average amounts of the nutrients in 
the manure are subtracted from the average amounts 
of the same nutrients in the food, and the results show 
the amounts of digested nutrients. With figures 
determined in this way we may easily calculate the 



206 ELEMENTS OF AGRICULTURE 

digestible nutrients in any given weight of food. For 
instance^ from the composition of timothy hay shown 
in Table V in the Appendix we learn that every 100 
pounds of such hay contains 5.9 pounds of protein, 2.5 
pounds of fat, 45 pounds of nitrogen-free extract, and 
29 pounds of fiber. Digestion experiments show that 
48 per cent of the protein, 57 per cent of the fat, 63 
per cent of the nitrogen-free extract, and 52 per cent 
of the fiber are digestible. Then every hundred pounds 
of timothy hay must, according to these figures, contain 
the following amounts of digestible nutrients: 2.8 
pounds of protein, 1.4 pounds of fat, 28.4 pounds of 
nitrogen-free extract and 15 pounds of fiber. 

A great many digestion experiments have been made 
with many different kinds of animals and foods. Such 
tests are necessary, for different animals have different 
powers of digestion. A cow, for instance, may digest 
more of a certain kind of food than a horse, a growing 
calf may digest more of a food than an old steer. Dif- 
ferent samples of the same food differ in the amounts 
of digestible nutrients they contain. It is only by 
making many tests, and taking their average that 
reliable figures can be obtained. The experiment 
stations of this and of other countries have made, and 
are making, many tests to determine the digestibility 
of all kinds of animal foods, and in Table VI of the 
Appendix will be found the averages of the most 
reliable of these tests for the foods shown in Table V. 
The figures giving the percentages of the nutrients 
digested are called digestion coefficients. With 
the figures in Tables V and YI one may easily calculate 



DIGESTIBILITY OF STOCK FOODS 20T 

the amounts of digestible nutrients in any of the foods 
there recorded. For the convenience of the student we 
have calculated the amounts of digestible nutrients in 
most of the foods shown in Table V, and the results 
are arranged in Table YII. The nitrogen-free extract 
and crude fiber are combined in this table, and the 
sum is given under carbohydrates. 

Questions 

1. On what does the value of a cattle food chiefly depend? 
2. In judging of the value of a cattle food what must be 
considered besides its composition? 3. How may the 
amounts of digestible nutrients in a food be determined? 
4. What are digestion coefficients? 

PROBLEMS 

1. Suppose we feed a horse 40 pounds of corn which con- 
tain 4 pounds of protein, and the manure resulting contains 

1 pound of protein, what per cent of the protein is digestible ? 

2. Suppose a cow is fed 30 pounds of clover hay, which 
contain 3 pounds of protein, and the manure resulting con- 
tains .96 of a pound of protein, what per cent of the protein 
is digestible? 

3. Suppose a steer is fed 30 pounds of ensilage containing 

2 pounds of crude fiber, and the manure resulting contains 
.76 of a pound of crude fiber, what per cent of the fiber is 
digestible? 



208 ilLEMENTS OF AGKTC^ULTURB 



CHAPTER XXXIX.—Calculating Rations for 
Animals 

200. Rations. — The food supplied an animal during 
any stated period is called a ration; thus the food of 
one day is called a day's ration. Calculating the differ- 
ent amounts of the food to be included in a ration is 
called compounding rations. The compounding of 
rations means the mixing of the proper amounts of 
digestible nutrients to keep the animal in good con- 
dition. 

201. Feeding Tests. — Different animals require dif- 
ferent amounts of digestible nutrients, and the same 
animal under different conditions requires different 
amounts. After a long walk we usually come home 
hungry; we need food to renew the portions of our 
body worn by the exercise of walking. The question 
is how much food is needed. We usually settle the 
question by eating till we are no longer hungry, and 
by this method eat too much, and make ourselves sick. 
Animals, too, if allowed the opportunity will often 
make themselves sick by overeating. Allow a horse 
to help himself from an oat or corn bin, and he will eat 
till he can hold no more; this usually results in a case 
of colic. To keep stall-fed animals in good condition, 
they must be supplied with the proper amounts of 
nutrients, and no more. To overfeed an animal is as 
bad as to underfeed it. In order to determine how much 
food different animals require, a great many careful 



CALCULATING RATIONS FOR ANI:MALS 209 

tests have been made. Many different kinds of animals 
in various parts of the world have been fed weighed 
amounts of food, in samples of which the digestible 
nutrients had been previously determined. In this 
manner the weights of digestible protein and non- 
nitrogenous matters necessary to keep the animal in 
good condition are determined. Such figures are called 
FEEDING STANDARDS. In Table VIII of the Appendix 
the average results of many such tests are recorded. 

202. Nutritive Ratio.— The last column, Table VIII, 
shows nutritive ratios. By nutritive ratio is meant 
the proportion of digestible protein to fat, nitrogen-free 
extract and fiber combined. To calculate the ratio we 
must start by multiplying the fat by 2 A; for the fat 
is considered nearly 2J times as valuable for food as the 
carbohydrates (nitrogen-free extract and crude fiber). 
Let us take as an example the corn fodder shown at 
the beginning of Table VII. We have A of a pound 
of fat X 2.4 = .96 + 11.6 carbohydrates = 12.56 -f- 1 
of protein = 12.56, giving a ratio of 1 to 12.56, which 
means that the food contains 12.56 times as much 
carbohydrates and fat as protein. We have the follow- 
ing formula: 

Fat X 2.4 + carbohydrates 

— — — : = nutritive ratio. 

Protein 

203. Compounding Rations. — Kow let us see how the 

figures in Table VIII may be applied. Suppose we have 
a horse doing ordinary farm work, and we wish to sup- 
ply him with the proper amount of food to enable him 
to do his work well and at the same time keep him in 
14 



210 ELEMENTS OF AGRICULTURE 

good condition. Onr horse weighs between 950 and 
1,000 pounds, and we have a supply of oats, shelled 
corn, and clover hay, with which to feed him. How 
can we mix these foods so as to supply him the proper 
amounts of protein, fat and carbohydrates? By refer- 
ring to Table VIII we find that a horse at moderate 
work, for every thousand pounds of live weight requires 
each day 22 pounds of dry matter, containing of diges- 
tible nutrients, 1.8 pounds of protein, .6 of a pound 
of fat and 11 pounds of carbohydrates; giving a nutri- 
tive ratio of 1 to 6.9. In mixing our foods to supply 
this ratio we will start by taking 10 pounds of corn. 
Eeferring to Table YII we find that this amount of 
corn contains 8.9 pounds of dry matter, .8 of a pound 
of digestible protein, .46 of a pound of digestible fat, 
and 6.59 pounds of digestible carbohydrates. Next we 
take 10 pounds of clover ha}', which we find from the 
same table contains 8.47 pounds of dry matter; and of 
digestible nutrients, .76 of a pound of protein, .20 of a 
pound of fat, and 3.84 pounds of carbohydrates. 
Adding these figures together we have 17.4 pounds of 
dry matter, 1.6 pounds of protein, .66 of a pound of fat, 
and 10.4 pounds of carbohydrates. To complete our 
required ration we need only 4.6 pounds of dry matter; 
therefore 10 pounds of oats would give more than is 
needed, so we will take 5 pounds. This amount of oats 
according to Table VII gives us 4.45 pounds of dry 
matter; and of digestible nutrients, .46 of a pound of 
protein, .21 of a pound of fat, and 2.36 pounds of 
carboh3^dratcs. Adding these figures to those for hay 
and corn we have: 



CALCULATING RATIONS FOR ANIMALS 



211 



Digestible JNutrients. 

Dry Carbo- 

Matter. Protein. Fat. hydrates. 

10 pounds shelled corn... 8.9 .80 .46 6.59 

10 pounds clover hay 8.5 .76 .20 3.84 

5 pounds oats 4.5 .46 .21 2.36 

Compounded ration 21.9 2.02 .87 12.79 

Required ration 22.0 1.80 .60 11.00 

Nutritive ratio in compounded ration, 1 to 7.3; required 
ratio, 1 to 6.9. 



These rations agree well enough, so let ns try 
another, sa}' one for a cow giving milk. Table YIII 
shows that a cow giving milk, for every thousand 
j^ounds of weight requires per day 28 pounds of dry 
matter containing of digestible nutrients, 2.5 pounds 
protein, .5 pound fat, and 12 pounds carbohydrates. 
But suppose our cow weighs only 800 pounds. We 
should then take only .8 of the ration or 22.1 pounds 
dry matter, 2 pounds protein, A pound of fat, and 9.G 
pounds carbohydrates. We have, to feed our cow, corn 
ensilage, cowpea hay, hay of mixed grasses, and wheat 
bran. As ensilage is a bulky food containing much 
water, let us start by taking 30 pounds of it, and as 
bran is a rich dry food, we should take much less of it, 
say 5 pounds. The amounts of these two foods together 
give us about 10 pounds of dry matter, leaving about 
12 pounds to be supplied by the two hays. As ensilage 
contains but little protein let us take the larger amount 
of pea hay which is rich in protein. We will take say 
8 pounds of the pea hay and 5 pounds of the mixed hay. 
Xow referring to Table YII we find that the amounts 
of food selected give the following figures : 



212 ELEMENTS OF AGRICULTURE 

^ Digestible Nutrients. 

Dry Carbo- 

Matter. Protein. Fat, hydrates. 

30 pounds Of ensilage 6.27 .27 .21 3.39 

5 pounds of bran 4.40 .61 .13 1.96 

8 pounds of pea hay 7.14 .86 .08 3.12 

5 pounds of mixed hay 4.35 .30 .06 2.05 

Compounded ration 22.16 2.04 .48 10.52 

Required ration 22.40 2.00 .40 9.60 

Nutritive ratio in compounded ration, 1 to 5.7; required 
ratio, 1 to 5.3. 

It is not necessary that the calculated ration should 
agree exactly with the standard. The agreement be- 
tween the standard and the two examples given is 
close enough for all practical purposes. The standards 
in Table VIII are intended merely as guides in mixing 
rations, not as fixed rules by which we must work. In 
calculating rations, find the amounts of digestible 
nutrients in the principal food to be used, and try 
combining with these figures those for varying amounts 
of the other foods till a ration is obtained giving a 
nutritive ratio as near as j^ossible to the standard. It 
is not necessary to use fractions of pounds in weighing 
the different foods. 

204. Weighing the Different Foods in the Ration. — 
It would of course require far too much labor to weigh 
out the different foods each time an animal is fed, and 
such care is not necessary. Grains, meals, bran, and 
other similar foods may be measured, and the weight 
of a given measure determined. Ensilage may also be 
measured, and so may root crops. For hay and other 
fodders the weights of the fodder held on a certain 



CALCULATINa RATIONS FOR ANIMALS 213 

fork or in a hamper should be determined once for all. 
With this knowledge the weight of fodder may be 
closely estimated without actual weighing at each 
feeding. 

Questions 

1. What is meant by a ration? 2. What is meant by nu- 
tritive ratio? 3. What are feeding standards? 4. How are 
feeding standards determined? 

PROBLEMS 

1. We wish to mix a ration for a fattening ox weighing 
1,000 pounds, and for food have decided to use 30 pounds 
corn ensilage, 5 pounds cottonseed-meal and 5 pounds mixed 
hay. How much wheat straw must be added to complete the 
ration? 

2. Suppose we have a herd of wool-growing sheep and 
wish to feed them during the winter. Our sheep weigh 
about 130 pounds each, so that eight sheep weigh about 
1,000 pounds. The food we have to give them consists of 
shelled corn and mixed hay. Calculate the amount of each 
food necessary to supply the proper ration. 

3. Calculate the nutritive ratio in a ration supplying 2.3 
pounds of protein, .88 pound fat and 14 pounds carbohy- 
drates. 



214 ELEMENTS OF AGEICULTURE 



CHAPTER XL.— Selecting Stock Foods 

205. Different Animals Require Different Foods. — 

The art of stock feeding does not consist simply in 
mixing certain proportions of digestible nutrients. The 
ration may contain the proper proportions of digestible 
nutrients, and yet be unfit for food. The taste of the 
animal fed must be considered. Different kinds of 
animals differ in their tastes for foods much as human 
beings do. The cow eats readily food that a horse will 
not touch, and the pig eats food that would be refused 
by either the cow or horse. The art of stock feeding 
consists in supplying animals not only the proper 
amounts of food, but also the proper kinds of food as 
well. 

206. Volume of Food. — Besides the digestible por- 
tions of the food, all animals require a certain volume 
of indigestible food. Nature has provided that they 
digest only a part of their food, and pass the undigested 
portion off as manure. It is possible to feed animals 
with certain foods all of which they can digest, and yet 
find that they do not do well on such a ration. Such 
foods are soon digested, leaving the stomach and intes- 
tines practically empty, and this condition of things is 
not good for the animal. Cattle, especialh^, require 
large amounts of food, as their stomachs are very large. 
The stomach of an ox is divided into four compart- 
ments, all of which together liold about 250 quarts. 
The stomach of the horse is much smaller, holding 



SELECTING STOCK FOODS 215 

only 17 to 19 quarts; and the stomach of the hog holds 
only 7 to 9 quarts. The iirst compartment of the 
stomach in cattle serves as a sort of storehouse for 
food when first swallowed. Cattle, after chewing and 
swallowing their food, hring it back into the mouth 
from this first stomach, and after chewing it again, 
sw^allow it. This process is called chewing the cud. 
Sheep as well as cattle chew the cud, but the horse and 
pig do not. 

207. All the Foods Produced on the Farm May Be 
Utilized. — The fact that different domestic animals 
l^refer different kinds of food enables the careful stock 
man to use to advantage all the food produced on his 
farm. Cattle eat coarse fodder that horses will not 
touch, and hogs eat many foods unfit for either horses 
or cattle. Every pound of food produced may be used 
for stock of some kind. The coarsest fodder, if properly 
prepared, is readily eaten by cattle; and wheat straw, 
a poor food in itself, is useful for mixing with rich foods 
such as wheat bran or cottonseed-meal. Very coarse 
fodder should be run throuo^h a shreddino- machine 
before it is fed. A shredding machine tears the fodder 
into bits, in which condition it is more palatable to the 
animal. It is well to dampen very dry fodder before 
feeding, both to render it more palatable and to prevent 
the dust from it entering the nose and lungs of the 
animal to which it is fed. Many horses contract bad 
coughs from the dust rising from very dry fodder. 

208. Experience and Observation Necessary. — The 
feeding standards in Table VIII are intended merely 
as guides for mixing the different foods that make up 



216 • ELEMENTS OF AGRICULTURE 

the ration. The kinds of food that make up the ration 
are determined according to the judgment of the person 
doing the feeding. Observation and experience are the 
best guides for selecting the proper foods, and every 
stock grower should, for his own satisfaction, try all 
the different stock foods within his reach. By keeping 
a record of each, he can determine which are best for 
his purpose. It is a bad plan to depend on only two or 
three foods; all animals like a variety of food, and if 
fed the same thing day after day they in time tire of it 
and lose their appetite. 

209. Cost of Foods. — Foods costing the most money 
are not always the best, nor are the foods costing the 
least money always the cheapest. The author had 
occasion a few years ago to make analyses of many 
kinds of stock foods, and the results of a few of these 
analyses may serve as examples : 

From a certain town a sample of food known as 

" 's Food for Stock and Poultry" was obtained. 

An analysis showed that this food contained in every 
hundred pounds, approximately, 16 pounds of protein, 
7J pounds of fat and 60 pounds of carbohydrates. An 
examination showed that the food consisted of wheat 
bran and corn-meal, with the addition of a little cotton- 
seed-meal. To the food had been added a strong-smell- 
ing powder called fenugreek, which is of no value either 
as a food or medicine. This stock food sold at 6 cents 
a pound or $120 a ton. From the same town, another 
sample of stock food, known as a mixed cattle food, was 
obtained. This food was also made up of wheat bran, 
corn-meal, and cottonseed-meal, but contained no fenu- 



SELECTIXG STOCK FOODS 21 T 

greek. An analysis showed that every hundred pounds 
contained, approximately, 17f pounds of protein, 6 
pounds of fat and 62} pounds of carbohydrates. This 
food sold for $17 a ton, and contained more nutrients 
than the food sold at $120. The digestibility of the two 
foods was practically the same. Persons buying the 
expensive food were paying $103 extra for the addition 
of a little worthless fenugreek. There are many so- 
called prepared stock foods on the market, and for the 
most part they are not worth the prices charged for 
them. In buying any sort of prepared food or mill 
product, if there is any doubt as to the quality, a sample 
should be sent to the nearest chemist for analysis. 

Questions 

1. In mixing a ration what other things besides the 
amount of digestible nutrients must be considered? 2. Why- 
is it important to supply animals food containing indigesti- 
ble as well as digestible compounds? 3. About how many- 
quarts does the stomach of an ox hold? 4. What is the 
capacity of the horse's stomach? 5. How is the stomach of 
the ox divided up? 6. What is the purpose of the first 
stomach of the ox? 7. What is meant by chewing the cud? 
8. How is it possible to utilize all the food products on the 
farm? 9. Why is it advisable to try many different kinds 
of food in feeding animals? 10. Of what value are most 
prepared stock foods? 



218 ELEMENTS OF AGRICULTURE 



PART VII.— Miscellaneous Topics 



CHAPTER XLI.— Birds 

210. Destruction of Birds. — In this age of ours a 
money value is the standard by which most things are 
judged. The first question is usually, " What is it 
worth ? "• Now, what are birds worth ? They are pretty: 
many of them sing, and most kindly disposed persons 
enjoy seeing them about, but have they an actual 
money value? This question has been answered time 
and again, and the answer is always the same. Birds 
are of value, and they are of value to every living 
creature on this earth. It is not simply the birds that 
supply food for man and beast that are of value, but 
those pretty, bright little things that come each spring 
to enliven our country — robins, blackbirds, redbirds, 
orioles, swallows, and a host of others. Every year they 
come with the spring, and many of them spend their 
summer with us, but not as welcome guests. They are 
greeted with guns, sling-shots, traps, stones, hunted by 
cats and dogs, robbed of their nests and eggs, perse- 
cuted by man and beast. Those unfortunates with 
bright, pretty feathers are killed that they may serve to 
ornament women's heads. We laugh at the poor Indian 
who decks himself with paint and feathers for some 
festive occasion; but each year thousands upon thou- 
sands of beautiful and useful birds are killed in order 
that women may adorn their heads, not with feathers 



BIRDS 219 

only, but with whole birds, copying the fashion of the 
painted savage whom they scorn. Many thousands too 
die each year by the hands of so-called sportsmen ; not 
game birds merely — such as turkeys, geese, duck, and 
partridges — but robins, larks, doves, nighthawks (bull- 
bats), martins, and many other useful birds. To the 
average man with a gun everything with feathers is a 
game bird, and he slaughters without mercy. To the 
small boy the destruction of birds and their nests is a 
never-failing source of delight, and the murder of many 
helpless birds a thing to boast of. He kills merely for 
the love of killing, gratifying his brute instincts by 
putting to death creatures too weak to defend them- 
selves against attack. Men, women, and children are 
united with animals in a war on birds. Animals kill 
for food; men and children mainly for the love of kill- 
ing; women to satisfy their vanity. It would seem that 
in this case the jeasts are endowed with higher motives 
than men and women. 

211. Value cT IBirds. — But you say, birds steal fruit, 
they injure grain crops, some of them kill chickens, 
and what use are they anyway ? Did you ever see a tree 
stripped of its leaves by caterpillars or other insects? 
Did you ever see a fine fruit orchard dead or dying as 
though swept by a fire? Did you ever see a field of 
grain or grass eaten by an army of worms? Did you 
ever see a garden destroyed by worms or insects? Such 
things happen every year, and are becoming more and 
more common. Great armies of insects are busy each 
year destroying crops, trees, grass, and every green 
thing. The birds are busy destroying these insects, and 



220 ELEMENTS OF AGRICULTUEE 

man is busy destroying the birds. Which is to succeed ? 
If man succeeds, the insects will be left in peace to 
grow and multiply, and the destruction of all i^lant life 
will certainly follow. Chapman gives us an admirable 
description of how birds are constantly busy destroying 
insects : " Consider for a moment/' he writes, " what 
the birds are doing for us in summer when the hum of 
insect life fills and becomes almost an inherent part 
of the atmosphere. 

" In the air, swallows and swifts are coursing rapidly 
to and fro, ever in pursuit of the insects which consti- 
tute their sole food. When they retire the nighthawks 
and whippoorwills will take up the chase, catching 
moths and other nocturnal insects which would escape 
day-flying birds. The flycatchers lie in wait, darting 
from ambush at passing prey, and with a suggestive 
click of the bill returning to their post. The warblers, 
light, active creatures, flutter about the terminal 
foliage, and, with almost the skill of a humming-bird, 
pick insects from leaf or blossom. "The vireos patiently 
explore the undersides of leaves and odd nooks and 
corners to see that no skulker escapes. The wood- 
peckers, nuthatches, and creepers attend to the tree 
trunks and limbs, examining carefully each inch of 
bark for insects' eggs and larvae, or excavating for the 
ants and borers they hear at work within. On the ground 
the hunt is continued by thrushes^ sparrows, and other 
birds who feed upon the innumerable forms of terres- 
trial insects. Few places in which insects exist are neg- 
lected; even some species which pass their earlier stages 



BIRDS 221 

or entire lives in the water are preyed upon by aquatic 
birds/'* 

But birds are useful in other wa3^s besides destroying 
harmful insects. There are many kinds of birds that 
live principally on the seed of weeds^ and in this way 
destroy great numbers of weeds which would other- 
wise grow up to the hurt of farmers. Then there are 
still other kinds that make their living on field mice, 
rats, larger insects — grasshoppers, etc. Let us consider 
the work done by each of these classes of birds, begin- 
ning with the insect-eater, or insectivorous bird. 

Questions 

1. How are birds received when they come in the spring? 
2. What harm do birds do? 3. What good do they do? 
4. Into what groups are birds divided? 5. What are insecti- 
vorous birds? 



*Report of Conn. Board of Agr., 1899, p. 76. 



222 ELEMENTS OF AGRICULTUEE 



CHAPTEK XLII.— Insectivorous Birds 

212. Damage Done by Insects. — Before taking up 
insectivorous birds, let its tr}^ to get some idea of the 
damage done to farm crops each year by insects. 

Harmful insects feed mainly on the young and tender 
foliage of growing plants, but they also attack the seed, 
fruit, stem, and roots. In fact every portion of the 
plant is used as food by various insects, and no plant is 
safe from their attacks. Of course, not all insects are 
harmful. There are insects that prey on injurious 
insects, but, unfortunately, the harmful insects far out- 
number the beneficial kinds. Birds prey largely on the 
injurious kinds. 

A careful estimate places the average damage done 
annually by insects in the State of Illinois at twenty 
millions of dollars, which means that the damage 
averages 56 cents to each acre.* Fifty-six cents per 
acre for the damage done by insects is hardly an over- 
estimate, and it is probable that there are few farmers 
whose crops are not damaged to this extent. But let 
us take for our example the State of Virginia and con- 
sider only the cultivated land. Forests we will not 
consider, though they are often much damaged by insect 
pests. We will assume that there are 9,000^000 acres 
of land under cultivation in Virginia^ and that the 
crops from this amount of land are damaged by insects 

*lleport of Conn. Board of Agr., 1899, p. 78. 



INSECTIVOEOUS BIRDS 223 

to the extent of only 50 cents per acre. This would 
mean that insects destroy each year in Virginia four 
and one-half million dollars^ worth of farm crops. If 
the damage were only 10 cents per acre, the loss would 
still be nearly a million dollars. But 50 cents is a low 
estimate, and we may safely say that each year in the 
State of Virginia four and one-half million dollars' 
worth of farm produce is destroyed by insects. This is 
an enormous loss, and the farmers should welcome any 
means of checking it. 

213. Insects Eaten by Birds. — ^ow, have we no 
means at hand of lessening the number of destructive 
insects? Birds that make insects their principal food 
must destroy great numbers. Anyone who is at all 
observant must have noticed how many birds are con- 
stantly pursuing insects. The robin is busy most of 
the day, hopping about on the ground picking up the 
insects that constitute its food; we have all seen these 
birds at work, and also the many birds feeding in the 
air and on the trees. We must have noticed them. But 
if better proof than our own observation is desired, we 
have it from good authority. " Professor Forbes, 
Director of the Illinois State Laboratory of Natural 
History, found 175 larvae of Bibio — a fly, which, in the 
larval stage, feeds on the root's of grass — in the 
stomach of a single robin, and the intestines contained 
probably as many more."* Another excellent authority 
states : " In a certain town where the elms had been 
ruined for several years, the cedar birds appeared and 
the elms were afterwards comparatively free from these 

*Report of Conn. Board of Agr,, 1899, p. 77. 



224 



ELEMENTS OF AGKICULTUKE 



destructive beetles. It has also been shown that thirty 
cedar birds would destroy 9,000 worms during the 
month when the cutworm caterpillar is exposed/^* 

We might add many hundred examples like the above 
to show the great number of insects destroyed by birds. 
It is very reasonable to suppose that the more birds we 
have about, the more insects will be eaten. Professor 
Forbes estimates the number of birds in Illinois at three 
individuals to the acre, f In Virginia there are probably 
as many birds to the acre as there are in Illinois, so we 
may assume that there are three birds to each acre of 
land in Virginia. This would give us for this State 
something like eighty million birds. Suppose that each 
bird destroys only one insect a day, it would mean 
the destruction of eighty million insects. One insect 
a day to each bird, however, is too low an estimate; 
twenty insects to each bird would be more probable. 
To be on the safe side, then, let us assume that two- 
thirds of the total number of birds, or 53,000,000, 
eat insects, and that each individual bird eats an 
average of ten insects a day. This would mean 530,- 
000,000 insects destroyed each day by birds. Could 
there be a more effective way of destroying them? 
Could we but add to the number of insect-eating birds 
within the state of Virginia only one individual to each 
acre of ground, it would mean the destruction of mil- 
lions of insects, and a saving of many thousand dollars 
to the farmers and fruit growers. Yet no efforts are 
made to increase the number of such birds; on the con- 

*Report of Conn. Board of Agr., 1899, p. 83. 
fibid, p. 77. 



,^.^ ITs^SECTIVOKOUS BIRDS 225 

trary, it is probable that the number of these insect- 
eaters is growing less each year. 

214. The Birds that Eat Insects. — Xow, what birds 
may be classed as insect-eaters ? There are birds that 
live almost exclusively on insects, eating practically 
no vegetable food; there are others that live on both 
insects and vegetable food; and there is still another 
class that lives almost exclusively on vegetable food, 
eating only a few insects. We can mention separately 
only a few of the commoner varieties of birds — those 
usually seen about the average farm: 

Under the class of insect-eaters we may mention 
swallows, of which there are several varieties; the best 
known being the barn-swallow, tree-swallow, eave or 
cliff-swallow, and the bank-swallow. These birds build 
about the dwellings of man, and may be seen during the 
day circling about in search of insects. As these birds 
live almost exclusively on insects, they are of much 
value, and their presence should be encouraged in every 
way possible. " It is said that cliff and barn-swallows 
can be induced to build their nests in a particular 
locality, otherwise suitable, by providing a quantity of 
mud to be used as mortar. Barn-swallows may also be 
encouraged by cutting a small hole in the gables of the 
barn."* The purple martin also belongs to this family 
of birds, and is very useful as an insect-destroyer. The 
so-called chimney-swallow is not a swallow at all, but 
should be called a swift. It, too, feeds largely on insects. 
In the afternoons of summer and fall, we often see 

*U. S. Dept. Agr. Farmers' Bulletin No. 54. 

15 



226 ELEMENTS OF AGRICULTURE 

numbers of nighthawks, commonly known as bullbats, 
darting about through the air in search of food. These 
birds live exclusively on insects, and should be pro- 
tected, instead of being shot. The whippoorwill is a 
bird that works entirely by night, and it, too, lives on 
insects. Of all the insect-eating birds that inhabit 
farms, there is none of more value than the common 
house wren. Fully 98 per cent of its food is made up 
of insects, most of which work destruction to farm 
crops. The kingbird is another insect-eater, and is also 
of value to the farmyard as a watchman, driving off 
birds of prey. The cuckoo also lives largely on insects, 
and is especially fond of caterpillars. The phoebe, a 
quiet little bird, lives almost exclusively on insects, and 
is a very valuable bird on the farm. There are five or 
six different kinds of woodpeckers in the eastern 
United States, and they destroy many insects that prey 
on fruit and forest trees. They also eat some vegetable 
food, but do little or no damage to crops. The meadow 
lark, or old-field lark, is another bird that makes its 
living largely on insects. Its vegetable food consists of 
the seed of weeds. So it is of benefit to the farm in 
two ways. The brown thrasher is another insect-de- 
stroyer, more than half of its food being made up of 
insects. The bluebird eats mostly insects, which make 
up fully three-fourths of its food. The Baltimore oriole, 
famous for its beauty and song, is another insect-de- 
stroyer, and should be made welcome everywhere. The 
robin is a bird well known to everyone, but its value 
to the farm is far from being known. The robin, while 
it eats some vegetable food, destroys many harmful 



INSECTIVOROUS BIRDS 227 

insects; about one-half of its food being made up of 
insects. The catbird, against which there is such an 
unreasonable prejudice, is another insect-destroyer; 
about one-half of its food consists of insects. It is 
claimed that the bird destro3^s some fruit; but even 
if it does, it pays for all it takes by destroying hundreds 
of harmful insects ; and in this way does more good than 
harm to the fruit grower. 

There are many other birds that destroy insects, but 
we have not space to mention them all individually, and 
tell of their good work; so we must pass on to consider 
the seed-eating birds. 

Questions 

1. How do insects damage growing crops? 2. At what 
stage of growth are most crops subject to the attacks of 
insects? 3. About what is the estimated damage per acre 
by insects in the State of Illinois? 4. About how many- 
birds are there to the acre in Illinois? 5. About how many- 
insects do birds eat a day in the State of Virginia? 6. Name 
a few of the best known insect-eating birds in your neigh- 
borhood. 7. Tell vv^hatyou know about the kind of food 
eaten by the different birds with which you are familiar. 

PROBLEMS 

1. Suppose the annual damage from insects in your State 
averages 30 cents per acre, what is the yearly damage for 
the State? 

2. Suppose there are four birds to the acre in your State, 
about how many will there be for the whole State? 

3. Suppose each bird in your State eats five insects a day, 
how iDaray will all the birds destroy in a week? 



228 ELEMENTS OF AGRICULTUEE 



CHAPTER XLIII.— Seed-Eating Birds 

215. The Destruction of Weeds. — The successful 
farmer must spend a part of his time and some money 
in fighting weeds. Tlie amount of time and money 
he spends depends on how clean he keeps his farm. 
Weeds have been well defined as plants in the wron 
place. Naturally all thrifty farmers are interested in 
the destruction of weeds. They plow them under, they 
dig them up, and pull them out by hand, and yet some 
escape to start a new crop the next season. Most weeds 
produce great crops of seed; some weeds are known 
that produce about one hundred thousand seed to a 
single plant. If there were not some means of destroy- 
ing at least a part of the seed produced by weeds, the 
world would soon be overrun with them. Fortunately, 
there are fully fifty different kinds of birds that eat the 
seed of weeds, and tlie amount of seed destroyed by 
these birds is enormous. We can only mention a few of 
the birds individually. 

216. Birds that Destroy Weeds.— Probably the best 
known seed-eating birds are sparrows. Beal says of the 
sparrows that "there are some forty species, with nearly 
as many subspecies, in North America, but their dif- 
ferences, both in plumage and habits, are in most cases 
too obscure to be readily recognized, and not more than 
half a dozen forms are generally known in any one 
locality.^'* 

*U. S. Dept. Agr. Farmers' BuUetin No. 54. 



SEED-EATING BIRDS 229 

To give some idea of the amount of seed eaten by 
sparrows, Beal has made some estimates for the State 
of Iowa. He gives us iigures for only one kind of spar- 
row, namely, the tree-sparrow,, which is very abundant 
in the Xorthern States. He begins by estimating that 
there are ten sparrows to each square mile, or one spar- 
row to sixty-four acres. H, as he says, each sparrow 
eats daily an average of one-fourth of an ounce of seed 
for two hundred days, they destroy in that State alone 
1,750,000 pounds, or 875 tons of weed-seed; allowing 
20,000 pounds to a car-load, this is enough seed to load 
a little over eighty-seven cars. Besides this one kind 
of sparrow there are many others that eat largely of 
seed, and the amount of seed destroyed must be much 
larger than these figures show. Suppose instead of be- 
ing eaten by birds this vast quantity of seed were to 
grow up as weeds, what would become of the farmers ? 
In the Southern States, while we have not the tree- 
sparrow, we have a number of equally useful varieties, 
such as the white-throated sparrow, the white-crowned 
sparrow, the song-sparrow, the field-sparrow, the fox- 
sparrow, and a number of others. Just stop a moment 
and try to think of the vast number of weed-seed eaten 
each winter by the sparrows in each State. Even the 
much abused English sparrow is known to eat the seed 
of many weeds. 

Beal says : " While sparrows are noted seed-eaters, 
they do not by any means confine themselves to a 
vegetable diet. During the summer, and especially in 
the breeding season, they eat many insects, and probably 
feed their young largely upon the same food. An ex- 



230 ELEMENTS OF AGRICULTURE 

amination of the stomachs of three species — the song 
sparrow, the chipping sparrow and the field sparrow — 
shows that about one-third of the food consists of in- 
sects, comprising many injurious beetles, such as snout- 
beetles or weevils, and leaf-beetles."* 

Besides the sparrow there are a number of other 
kinds of birds noted as seed-destroyers. The goldfinch, 
or wild canar}^, is very useful in this respect. Eedbirds, 
horned larks, and blackbirds are also seed-eaters. The 
blackbirds with which we of the southeastern States 
are most familiar are the crow blackbird, or grackle, 
and the red-winged blackbird. Both of these birds are 
accused of stealing grain from cultivated fields, and it 
is very probable that they do some damage in this way; 
but, on the other hand, they eat quantities of weed-seed 
and also many insects. 

Besides the birds already mentioned, there are several 
so-called game birds that are seed-eaters. The ([uail, 
or bobwhite, lives largely on the seed of weeds, and does 
no harm to grain fields. The mourning dove is another 
bird that eats great quantities of weed-seed. 

Dr. Sylvester Judd, of the United States Department 
of Agriculture, says of seed-eating birds: " N'o less than 
fifty different birds act as weed-destroyers, and the 
noxious plants which they help to eradicate number 
more than threescore species." f 

217. Birds and Cultivated Crops. — On the other hand, 
it is undoubtedly true that some birds do damage to 
both grain crops and fruit crops. The crow and the 



*U. S. Dept. Agr. Farmers' Bulletin No. 54. 
tYearbook U. S. Dept. Agr., 1898, p. 232. 



SEED-KATING BIRDS 231 

two kinds of blackbirds already mentioned are the chief 
offenders, and in some sections of the country they are 
considered pests. Where the blackbirds gather in very 
laro-e flocks they do considerable damage to grain. But 
it is very ])robable that the destruction of grain is due 
to the lack of other food, for even when they can get 
cultivated grain these birds eat weed-seed and insects, 
and while they do some damage they certainly do some 
good. 

The crow is accused of pulling up young corn, and is 
probably guilty of this crime; but, on the other hand, 
about 2d per cent of the crow's food consists of harmful 
insects, and the number of such insects destroyed by 
crows must be immense. 

liobins, catbirds, and mocking-birds are often accused 
of taking fruit, but the best testimony goes to show 
that the value of the fruit eaten by them is but small, 
and is paid for many times over by the number of harm- 
ful insects destroyed. 

Questions 

1. What aid the farmer in his fight against weeds? 
2. About how many kinds of birds are known to eat the 
seed of weeds? 3. Name some of the best known seed- 
eating birds. 4, Give some idea of the amount of seed 
eaten by the tree sparrov/ in Iowa. 5. What can you say 
in defense of the blackbird and the crow? 

PROBLEM 

Suppose that in your State there are ten sparrows to each 
square mile, and that each sparrow eats one-fourth of an 
ounce of seed a day for one hundred and fifty days. How 
many pounds of seed will be eaten during that time in the 
State? How many car-loads will that amount of seed 
make, allowing 20,000 pounds to the car? 



232 ELEMENTS OF AGRICULTURE 



CHx\PTER XLIV.— Birds of Prey 

218. Prejudice Against Hawks and Owls.— We come 
now to a class of birds a part of whose food consists of 
small animals and birds. They are known as birds of 
prey. The birds of prey in which we are interested are 
generally known as. hawks and owls, and of both there 
are a number of different kinds. Against all birds of 
prey alike, there exists the strongest prejudice; they 
are without exception condemned, and, whenever the 
opportunity offers, executed without trial. This con- 
demnation of all birds of prey without trial is hardly 
just. We accord to our basest criminals a patient hear- 
ing. Why, then, should we not listen to a few words 
in defence of birds of prey? But few people will ever 
listen to a word spoken in defence of hawks or owls; 
they condemn the whole class. The innocent must 
suffer for the sins of the guilt}', for but few persons are 
willing to believe in an innocent hawk or owl. Yet 
there are hawks and owls not only innocent of all wrong 
against man, but actually of great benefit to agriculture. 
It is certainly unjust to condemn these birds to death 
because a few of their cousins have been known to steal 
poultry. It would be just as reasonable to condemn a 
whole family to death because one member was a thief; 
or to judge the character of the human race by a few 
criminals. But, you may object, how can this preju- 
dice against hawks and owls have become so universal 
without good foundation? That there is some founda- 



BIRDS OF PREY 233 

tion for the feeling is very true. There are hawks and 
owls that attack poultry or small game whenever the 
opportunity offers, hut this is by no means true of the 
whole race. There are many kinds of hawks and owls 
that are never known to touch poultry. Unfortunately, 
few persons can distinguish the different kinds of hawks 
or owls. They see some bird of prey attack their fowls 
and at once condemn, and, whenever possible, kill all 
birds that resemble it. In doing this they kill many 
innocent birds, and very probably never reach the guilty 
one; for the birds that rob the henroosts are very quick 
and shy, and fully realize the danger from a gun. On 
the other hand, their cousins who never touch a domes- 
tic fowl, and come, conscious of their innocence, in 
search of mice or insects, are greeted with shot intended 
for the thief. 

Unfortunately, it would require far too much space 
for us to attempt to describe each kind of hawk and 
owl. We can, however, tell of some of their good deeds 
as compared with the harm that they do, and urge on 
all to give to these valuable birds at least a fair trial. 
The harm that these birds do is easily told; the good 
that they do would fill a volume. Let us see what they 
have done to bring upon themselves the curse of man. 

219. Harm Done by Hawks and Owls. — The greatest 
crime of which these birds are accused is the destruction 
of poultry and game birds. Now, there are only two 
kinds of hawks commonly found in the United States 
that feed principally on the flesh of other birds. These 
are known as Cooper^s hawk, and the sharp-shinned 
hawk, and are much alike in appearance^ Cooper's hawk 



234 ELEMENTS OF AGRICULTlTRE 

being the larger. These birds are very quiet and shy, 
darting suddenly on their prey from some hiding-place. 
Earely are they seen soaring over fields or heard calling. 
There are two other bird-eating hawks sometimes seen 
in the country, the goshawk and the duck-hawk, but, 
fortunately, they are few in numbers. These four kinds 
of hawk are harmful, as they destroy many useful birds, 
and do little, if any, good. All the other hawks and 
owls known in the United States do good as well as 
harm. Some kinds are entirely beneficial, others prin- 
cipally beneficial, and still others in which the beneficial 
and harmful qualities are about equally balanced. To 
recognize these many kinds of birds requires more time 
and study than the average farmer can devote to it. 
How then can he punish the guilty without the innocent 
sufl^ering? Chapman says: " The only safe way to give 
justice to whom justice is due is to kill only the hawks 
we actually see taking our chickens, and not murder 
indiscriminately every member of the hawk family."* 

There are only a few owls known in this country that 
ever disturb poultry, and they also do much good in 
destroying many mice and rats. The owls work only 
at night, and when poultry are provided with a home 
they are perfectly safe from this bird. 

220. Value to the Farmer of Birds of Prey. — In the 
report for 1886, Dr. C. H. Merriam, chief of the 
Biographical Survey of the Department of Agriculture, 
gives some interesting figures showing the value of birds 
of prey in Pennsylvania. " On the 23d of June, 1885/^ 



♦Report of Conn. Board of Agr., 1899, p. 103. 



BIRDS OF PREY 235 

he tells us, " the Legislature of Pennsylvania passed an 
act known as the ^scalp act/ ostensibly ^for the benefit 
of agriculture/ which provides a bounty of 50 cents 
each on hawks, owls, weasels, and minks killed within 
the limits of the State, and a fee of 20 cents to the 
notary or justice taking the affidavit. 

^' By virtue of this act about $90,000 has been paid 
in bounties during the year and a half that has elapsed 
since the law went into eft'ect. This represents the 
destruction of at least 128,571 of the above-mentioned 
animals, most of which w^ere hawks and owls. 

" Granting that 5,000 chickens are killed annually 
in Pennsylvania by hawks and owls, and that they are 
worth 25 cents each (a liberal estimate in view of the 
fact that a large portion of them are killed when very 
young), the total loss would be $1,250, and the poultry 
killed in a year and a half would be worth $1,875. Hence 
it appears that during the past eighteen months the 
State of Pennsylvania has expended $90,000 to save the 
farmer a loss of $1,875. But this estimate by no means 
represents the actual loss to the farmer and taxpayer 
of the State. It is within bounds to say that in the 
course of a year every hawk and owl destroys at least 
a thousand mice or their equivalent in insects, and 
that each mouse or its equivalent so destroyed would 
cause the farmers a loss of two cents per annum. There- 
fore, omitting all reference to the numerous increase in 
tlie numbers of these noxious animals when nature^s 
means of holding them in check has been removed, the 
lowest possible estimate of the value to the farmer of 



236 ELEMENTS OF AGRICULTUKE 

each hawk, owl, and weasel would be $20 a year, or, $30 
in a 3Tar and a half. 

" Hence, in addition to the $90,000 actually expended 
by the State in destroying 128,571 of its benefactors, 
it has incurred a loss to its agricultural interests of at 
least $3,857,130, or a total loss of $3,947,130 in a year 
and a half, which is at the rate of $2,631,420 per annum. 
In other words, the State has thrown away $2,105 for 
every dollar saved! And even this does not represent 
fairly the full loss, for the slaughter of such a vast 
number of predaceous birds and mammals is almost 
certain to be followed by a correspondingly enormous 
increase in the numbers of mice and insects formerly 
held in check by them, and it will take many years to 
restore the balance thus blindly destroyed through 
ignorance of the economic relations of Our common 
birds and mammals."* 

A statement such as this from so reliable an authority 
as Dr. ]\rerriam should sro far towards convincino- us 
of the folly of destroying all kinds of hawks and owls. 

Questions 

1. What is meant by birds of prey? 2. Name the two 
commonest kinds of birds of prey. 3. Can you explain why 
such a strong prejudice exists against all hawks and owls 
alike? 4. How do most hawks and owls benefit farmers? 

5. About how many kinds of hawks are there in the United 
States that live exclusively on the flesh of other birds? 

6. Name the two commonly found in this country that live 
on. the flesh of other birds. 7. Give an account of the work- 
ing of the "Scalp Act" in Pennsylvania. 

♦Reportof Conn. Board of Agr,, 1899, p, 94. ^^ V 



BIRDS OF PREY 237 



PROBLEM 



Take the total number of acres of cultivated land in your 
State, and suppose there are two field mice to each acre, 
and that each mouse eats two cents worth of food per year. 
What is the value of the food eaten by the mice? If the 
hawks and owls eat one mouse for each two acres of land, 
what is the value of food saved? 



238 ELEMENTS OF AGRICULTURE 



CHAPTER XLY.— Forestry 

221. Definition. — Forestry is the art of growing and 
caring for trees; it is tree-farming. In this great conn- 
tr}^ of ours we are inclined to look on tree-farming as 
a useless occupation. With such vast forests as ours 
it seems useless to plant and grow more trees. But at 
the present rate, how long will our forests last? Each 
year many thousand trees are cut, and it takes many 
years for others to grow in their place. A great tree 
may be cut down in a few minutes ; but it requires fifty 
to one hundred years for another to grow in its place. 
Our forests are being cut away much faster than others 
are growing, and unless our government takes some 
measure to protect them, the forests of this country 
will all be destroyed. 

222. Value of Forests. — Besides suppl3dng timber, 
forests are of value in many ways : 

(1) In the first place forests have a great influence 
on the climate of a country. The trees through their 
leaves give off vast quantities of water, which serves to 
keep the air in the immediate vicinity of the forest 
moist. The moisture in the air serves to equalize the 
temperature, preventing sudden extremes of heat and 
cold. 

(2) Forests prevent excessive surface washing, 
causing the rains and snow to soak into the soil; thus 
increasing the flow of water from springs, wells, and 
creeks, and at the same time preventing floods. The 



FORESTRY 239 

great floods that occur each year in our rivers are, in 
a I'dTge measure, due to the cutting away of the forest 
about the sources of the rivers. There being no trees 
to stop ite flow, the water rushes away in gullies to 
increase the volume of creeks and rivers. The dreadful 
floods that take place each year in the great Mississippi 
River are no doubt made worse by the cutting away of 
the forests which surround its headwaters. There is 
every reason to believe that the floods in this river will 
grow worse as more of the forest in the valleys is cut 
away. 

(3) Forests prevent in a great measure the surface 
evaporation \\^hich takes away such vast quantities of 
water from treeless soil. Through surface evaporation 
and surface \vashing, soils from which trees have been 
cut, unless continually cultivated, are apt to suffer. The 
cutting of timber is often followed by forest fires that 
destroy the undergrowth, leaving the soil bare to the 
action of wind and rain. In this condition it loses 
moisture, loses fertility, and quickly becomes waste 
land. The cutting away of forests always lessens the 
water supply. 

(4) Forests are a great protection against wind- 
storms; they protect cultivated crops from both the 
cold winds of winter and the hot, drying winds of 
summer. 

223. Destruction of Forests. — Vast numbers of trees 
are cut every year for timber, and often the cutting is 
so carelessly done that many young trees are injured 
or destroyed. The modern process of manufacturing 
paper from wood pulp is also responsible for the 



240 ELEMENTS OF AGRICULTURE 

destruction of much timber. Soft timber is principally 
used in this process, and the amount of timber cut 
annually is immense. But the great forest destroyer 
is fire; each year vast areas of wooded land are burned 
over, and most of the young timber destroyed. After 
a forest has been cut, the young timber, if left undis- 
turbed, will in twenty-five to forty years produce a new 
forest, but after a fire there are few young trees left 
to grow. Each State has laws against starting forest 
fires, imposing as penalties heavy fines or imprisonment. 
Unfortunately, the law is never enforced, and fires that 
destroy thousands of dollars' worth of. timber are some- 
times started merely for the sake of obtaining a few 
chestnuts. Besides destroying the young growth, forest 
fires, which usually occur in the fall, leave the land 
comparatively bare to the action of winter rains, which 
do much injury to the exposed soil. 

Lumber companies buy up great areas of forest land 
merely for the lumber; they cut off the trees, caring 
nothiug for another crop, and after obtaining the lum- 
ber often leave the land to the action of fire and water. 
Under the present system of management the forests 
of the United States will certainly be destroyed in a 
comparatively few years, and the next generation will 
have to begin to grow trees as a regular crop. Conserva- 
tive estimates show that at the present rate of destruc- 
tion the forests of the United States will not last more 
than fifty years. 

224. Tree-Growing for Profit. — ^Forestry among 
other things teaches us how to grow crops of trees for 
market. By exercising the proper amount of care and 



FORESTRY . 241 

following a few simple rules, any one who owns timber 
land may harvest a crop of timber just as regularly as 
he harvests wheat or corn. Let us suppose the ease of 
a farmer who owns 200 acres of woodland and wishes 
to derive an income from the sale of timber. Now, he 
can in a short time cut all of his trees that are fit for 
lumber, but if he wishes another crop from the same 
land he must wait many years. If, however, he wishes 
to derive a steady income from his timber he can cut 
only a part of it each year. He can divide his 200 
acres into sections of say ten acres each, and cut the 
timber from one section each year; being careful to 
protect the young timber from harm. By the time he 
has cut over his 200 acres the young timber on the first 
ten acres cut has had twenty years added to its growth, 
and much of it will" be ready for cutting. In this way 
he derives a steady annual income from his timber. 
Instead of cutting each year, he may cut a certain area 
every two, three, or four years; say twenty acres every 
other year, or twenty-five or thirty acres every three 
y^ears. By following some system such as this he can 
derive a steady income from his timber land, and yet 
hand it down to future generations uninjured. 

225. Growing Trees for Shade or Ornament. — Aside 
from their value in forests, trees are of value for orna- 
mental purposes and for the production of shade. How 
delightful after a hot walk to enter the cool shade of 
a group of trees! Man or beast toiling along a hot, 
dusty road hails with joy the appearance of a tree, yet 
how few of our public highways are provided with shade 
trees. In building a road the destruction of all shade 



242 ELEMENTS OF AGEICULTURE 

trees is often the first object. Miles and miles of road 
stretch away without so much as a bush to shield the 
traveler from the fierce summer sun. The idea prevails 
that trees keep a roadbed damp, but this is true only 
where the soil is naturally very damp. A properly 
constructed road is never injured by shade trees, but on 
the other hand is made very much more comfortable 
for travelers. 

No pasture should be without its group of shade 
trees; if unprovided with shade, animals sufl^er very 
much from the summer sun. In the heat of the day 
they love to collect in the shade of some tree and w^ait 
for the cooler hours of the day, during which they feed. 
No pasture is complete without its shade trees for the 
protection of animals during the heat of the day. 

For ornamenting and shading ^ the grounds about 
dwellings, trees are often grown, and for this purpose 
various kinds of trees and shrubs are used according 
to the fancy of the owner. No country home is com- 
plete without its setting of ornamental trees or shrubs, 
^nd the market value of a place may be increased by a 
growth of trees or shrubs about the house. 

Questions 

1. What is forestry? 2. Have forests any effect on the 
climate of a country? 3. If so, how? 4. How do forests 
protect the surface ol the land? 5. How do forests check 
the formation of floods? 6. How do forests protect the soil 
from surface evaporation? 7. How are forests destroyed? 
8. Is there any law in your State against starting forest 
fires? 9. Does the cutting away of the older trees neces- 
sarily destroy a forest? 10. How may a piece of wood- 
land be made to yield an annual crop of timber? 11. Of 
what value are trees in a pasture? 12. Of what value are 
trees planted about a home? 



KOADS 243 



CHAPTER XLVI.— EOADS 

226. Growth of Interest in Good Roads. — There is an 
old saying to the effect that one may judge of the civili- 
zation of a country by its roads — the better the roads, 
the higher the civihzation. Savages have no roads; the 
old Romans built roads that are in use to-day. France, 
Germany, England, and the older countries of Europe 
have far better roads than we have in the United States. 
It is in only a few of the more progressive States of our 
country that any roads worthy of being called good are 
to be found. But the interest in good roads is grow- 
ing, and their value to the country through which they 
run is gradually being recognized. It is a hard matter 
to convince the tax-payer that a few dollars expended 
on road improvement will prove a paying investment; 
but the lesson is being learned, and will in time result 
in good roads. 

227. What is Meant by a Good Road. — Xow, what is 
meant by a good road? By the term good road, as 
ordinarily used, is meant a permanent road, the surface 
of which remains hard and smooth regardless of the 
weather, and which may be easily traveled at all seasons. 
It is a road built to be used by many generations. ^lost 
of our so-called roads are not really roads at all; they 
are trails, and are moved about to suit existing condi- 
tions. The building of roads such as are generally 
known in this country is a simple process, one that has 
been handed down for thousands of years. The first 



244 ELEMENTS OF AGRICULTURE 

step is to remove trees and other impassible obstruc- 
tions; in enterprising communities the stumps are 
sometimes dug up^ but the usual method is to leave 
them to be worn away by time and the wheels of passing 
vehicles. If the land be of sufficient value, the trail is 
fenced on either side to prevent its becoming too wide. 
Over this clearing, which is expected to grow with no 
assistance into a fully developed road, one vehicle fol- 
lows in the track of another until a well-marked way is 
established; and usually deep ruts are cut into the earth, 
and in damp places great pools of mud are churned up. 
When the ruts and mudholes become too deep to be 
conveniently filled with loose stones, or old fence rails, 
a new trail is opened around them. In this manner 
the course of the road is constantly changing. It is 
seldom that any grading is attempted. The trail wan- 
ders across the country from house to house, dodging 
the worst obstacles, and finally, after many windings, 
reaching its destination. 

The building of permanent highways is the business 
of the engineer, but every farmer should know some- 
thing of road-making and road-mending. 

228. Dirt Roads. — A dirt road is one that uses the 
natural surface of the ground with no attempt at im- 
provement except such as is obtained by drainage and 
grading. 

(1) In locating roads of any kind the first object 
should be to avoid steep grades. On dirt roads the grade 
should never be more than 7 per cent, which means a 
rise of 7 feet in every 100, or 369 feet per mile. As 
the steepness of the grade increases, the load hauled 



KOADS 245 

must decrease. According to Gillespie, if a horse can 
pull on a level 1,000 pounds; on a rise of 1 foot in 100, 
or 1 per cent, he can pull 900 pounds; on a rise of 1 foot 
in 50, or 2 per cent, he can pull 810 pounds; on a rise 
of 1 foot in 25, or -1 per cent, he can pull 51:0 pounds; 
and on a rise of 1 foot in 10, or 10 per cent, he can pull 
only 250 pounds. These figures show how important it 
is to avoid very, steep grades. 

(2) Good drainage is equally as important as good 
grades. Wet spots in the road, if neglected, soon become 
mudholes which prevent the hauling of anything but 
light loads. All wet portions of the road should be 
underdrained, just as wet fields are drained, the drains 




Fig. 24. — Section of macadam road with dirt tracks on either side. 
Shows ditches for surface drainage. (After a drawing in Yearbook, 
U. S. Dept. Agr., 1894, page 502.) 

being constructed in the same way. To carry off the 
surface drainage, open ditches on either side of the road 
should be constructed. The drainage ditches must, of 
course, have some outlet into some creek or gully. A 
few dollars carefully expended in draining a road may 
change an almost impassable road into a fairly good one. 
Unless properly drained no road can be kept in good 
condition. 

(3) The surface of the road should be wide enough 
to accommodate all travel, and the center should be 
higher than the sides. Fig. 24 shows how the surface 
of a well constructed road is built up. The center of 
the road should be just high enough above the ditches 



246 



ELEMETs'TS OF AGRICULTURE 



to cause all the surface water to run off. If too high, it 
is apt to wash. 

229. Stone Roads. — However well graded and drained 
dirt roads may he, they are certain to hecome muddy in 
wet weather; and from the passing of many vehicles, 
are much cut up into holes and ruts. To avoid this, the 
surface of the road or track may be covered with some 
hard material, such as broken rock, gravel, or oyster 
shells, which does not become soft in wei weather. 
Broken rock is the material most generally employed, 
and v\'hen properly used makes the most durable of all 
roads. There are two kinds of stone roads in general 




Fig. 25.— Section of macadam 
road. 



Fig. 26. 
road. 



w7//7?//m7mm. 

Section of telford 



use. One was designed by a Scotchman named 
Macadam, and is called a macadam road, the other v/as 
designed by another Scotchman named Telford, and is 
called a telford road. 

230. Macadam Roads. — The macadam road is built 
by using first a layer of broken rocks, none of the pieces 
to exceed three inches in diameter; the layer is rolled 
and packed. On this is placed another layer of smaller 
pieces of crushed rock, which is likewise rolled and 
packed. Lastly, a layer of finely crushed rock is put on, 
and, after being wet, is heavily rolled. 

231. Telford Roads. — The telford road is somewhat 
similar to the macadam, except that in place of the first 



EOADS 247 

layer of coarse broken rock, a laj^er of flat stones is laid 
in a regular course. On this the road is bnilt up like 
the macadam. Fig. 25 shows a section of a macadam 
road, and Fig. 26 a section of telford. 

A well constructed macadam or telford road will last 
for man}^ years, and costs little or nothing to keep in 
good repair, Stone roads should have dirt tracks on one 
or both sides. A dirt track is pleasant to use in dry 
weather, and saves wear on the stone track. Fig. 24 
shows such a road. 

232. Value of Good Roads to a Community. — Good 
roads provide better schools and better education, bet- 
ter churches and better morals, better health and 
greater happiness, more money and better business. 

(1) The value of country schools depends largely on 
the condition of the roads. When the roads become 
very bad, many children are prevented from attending 
school regularl}', and both the school and children 
suffer. It is not unusual for country schools to be 
closed for weeks at a time on account of the condition 
of the roads, ^lany country people who wish to provide 
their children a good education are forced to move into 
some town to secure it. It is useless to expect first-class 
country schools without good country roads. 

(2) Churches in the country are as much dependent 
on good roads as country schools are. Wlien the roads 
are very bad, many people stay away from church, the 
church suffers, and the people gradually become indif- 
ferent about attending at all. They become lax, and the 
morals of the community suffer. A country without 



S48 ELEMENTS OF AGRICULTURE 

good roads can have neither first-class schools nor 
first-class churches. 

(3) The happiness of most people is, to a large 
measure, dependent on the society of their -neighbors. 
Few people can be happy when forced to lead the life 
of a hermit. In many country districts the women and 
children are for months cut off from all society. They 
become practically prisoners, for not only are they cut 
off from society, but they are prevented from taking 
any form of outdoor exercise. They are confined to the 
house or yard, and sufl'er both physically and mentally. 

It is no very unusual thing for persons in the country 
to be far removed from all medical assistance; and 
persons cut off from the doctor have died from want of 
proper treatment. Good roads bring more and better 
society, more health and happiness, and better doctors. 

(4) By greatly reducing the cost of marketing crops, 
good roads increase the farmers profit. The old saying, 
"time is money/^ is particularly apj^licable to the 
farmer during his busy seasons. Over good roads he can 
in the same time handle almost twice as much produce 
with less wear and tear on his teams than over roads 
that are full of rocks and mudholes. 

When we remember that all the produce of the 
farm, in order to find a market, must pass over some 
sort of road, we can realize how important is the ques- 
tion of good roads to the farmer. In this connection, 
some figures prepared by the U. S. Department of 
Agriculture are of interest: 



ROADS 



249 



Cost of Hauling Farm Produce in the United States. 





Ex. 


fco 


» 


25 W 




O 


^^ 


» 


O H 






Ph 


HO 




K 


^^ 


^ W 


p^s 




H 


It 


0)3 






< J 


-<-< tf 


■^ ^ 


►j^a 




Pi D 


« o o 


^ 5 


i^ tf^ 






g.js 


t>H 


gf^o 




<^ 


-< 


< 


i^ 




MILES 


POUNDS 


CENTS 




Eastern States 


5.9 
6.9 


2,216 


32 

27 


$1.89 


Northern States 


1.86 


Middle-Southern States 


8.8 




31 


2.72 


Cotton States 


12.6 


1,397 


25 


3.05 


Prairie States 


8.8 


2,409 


22 


1.94 


Pacific Coast and Mountain States. . 


23.3 


2,197 


22 


5.12 


Average for the United States 


12.1 


2,002 


25 


$3.02 



" The total weight of farm products in 1895 was 
estimated at 219,824,227 tons; if the forest products 
hauled over the public roads be added to this, we get 
313,349,227 tons, which at $3.02 per ton, makes a total 
for the annual cost of hauling on public roads of 
$946,414,665. Xearly, if not quite, two-thirds of this 
vast expense may be saved by road improvement, and 
this at a total cost of not exceeding the losses of three, 
or at most four, years by bad roads." (Circular 19, 
Office of Road Inquiry, U. S. Dept. Agr.)* 

Questions 

1. How may the civilization of a country be judged? 

2. What countries have the best roads at the present time? 

3. What is meant by a good road? 4. Are there many miles 



''Handbook for Farmers and Dairymen, F. W. Woll, p. 160. 



250 ELEMENTS OF AGRICULTURE 

of good road in your State? 5. In locating a road why is it 
important to consider the grade? 6. Why is the drainage 
of a road important? 7. What happens to the surface of a 
dirt road in wet weather? 8. What is a stone road? 
9. Name two well known kinds of stone roads. 10. Tell 
how a macadam road is constructed. 11. Tell how a telford 
road is constructed. 12. How do good roads improve coun- 
try schools? 13. What effect have good roads on country 
churches and on the morals of a community? 14. How do 
good roads affect the society of a community? 

PROBLEM 

If it costs 30 cents to haul one ton a mile, how much will 
it cost to haul 5,000 pounds of tobacco eight miles? 



Appendix of Useful Tables. 



APPENDIX 



253 



COMPOSITION OP MANURES 



Table I 
Nitrogenous Manures 





Pounds Per Hundred. 


ARTICLE. 


Nitrogen. 


Phosphoric 
Acid. 


Potash. 


Sodium nitrate. 


151^ to 16 
19 to 201^ 
12 to 14 

10 toll 

11 to 123^ 
5 to 6 

7 to 9 
61^ to 7K 










Dried blood, high grade 

Dried blood, low grade 


'3 "to' "5 
1 to 2 

11 to 14 
6 to 8 
l>^to 2 




Concentrated tankage. ... . 




Tankage, bone 




Dried fish scrap 




Cottonseed-meal 


2 to 3 







Table II 

Phosphatic Manures 





Pounds Per Hundred. 


ARTICLE. 


Phosphoric acid. 


Nitrogen. 




Available. 


Insoluble. 


Total. 


§. C. phosphate rock 

Florida phosphate rock ,. . 

S. C. dissolved rock 

Florida dissolved rock 

Ground bone 

Steamed bone 


12' to' 15 
14 to 16 

5 to 8 

6 to 9 
13 to 15 


26 to 28 

33 to 35 

Ito 3 

Ito 4 

15 to 17 

16 to 20 
2 to 3 


26 to 28 
33 to 35 
13 to 16 
16 to 20 
20 to 25 
22 to 29 
15 to 17 


VA to 23^ 
2 to 3 


Dissolved bone.. .. 







254 



ELEMENTS OF AGRICULTURE 



Composition of Manures— Continued 



Table III 
Potasslc Manures 



ARTICLE. 


Pounds Per Hundred 




Potash. 


Phosphoric 
A6id. 


Lime. 


Chlorine. 


Muriate of potash 


50 
48 to 52 
12 to 123^ 
16 to 20 
20 to 30 
2 to 8 
1 to 2 
5 to 8 




"io" 

30 to 35 

35 to 40 

33^ 


45 to 48 


Sulpliate of potash 

Kainit 




34 to 134 




30 to 32 


Sylvanit 




42 to 46 


Cottonseed-hull ashes 

Wood ashes, unleached . . . 
Wood ashes, leached 


7 to 9 
1 to2 

1 to 13^ 

3 to 5 









Table IV 
Average Composition of Farm Manures 





Pounds Per Hundred. 


ARTICLE. 


Moisture. 


Nitrogen. 


Phosphoric 
Acid. 


Potash. 


Lime. 


Cow manure, fresh 

Horse manure 

Sheep manure 

Hog manure 

Hen dung 

Mixed stable ma- 
nure . 


80.3 
71.3 
64.6 
72.4 
56.0 

75.0 


0.38 
0.58 
0.83 
0.45 
1.63 

0.50 


0.16 
0.28 
0.23 
0.19 
1.54 

0.26 


0.36 
0.53 
0.67 
0.60 
0.85 

0.63 


0.31 
0.21 
0.33 
0.08 
0.24 

70 







APPENDIX 



255 



STOCK FOODS 



Table V 
Average Composition of Stock Foods 





Pounds Petr Hundred. 


NAME OF FOOD. 


S 


11 


i 


5 « 




CO 

< 


Oreen Food and Ensilage. 


79.3 
69.4 
76.6 
71.7 
65.1 
70.8 
83.6 
79.1 

40.5 
9.5 
13.2 
12.9 
15.3 
10.7 
9.2 
9.6 

90.5 
68.4 

10.9 
11.0 
10.9 
10.5 
12.2 
9.9 

15.0 
15.1 

9.1 
11.9 
12.1 

8.5 
10.5 


1.8 
1.6 
2.6 
2.2 
4.1 
4.4 
2.4 
1.7 

3.8 
8.9 
5.9 
10.1 
12.3 
16.6 
4.0 
3.4 

1.1 
1.9 

10.5 
11.8 
12.4 
11.9 
24.2 
19.4 

9.2 
8.5 
9.0 
15.4 
15.6 
43.3 
4.4 


0.5 
1.6 
0.6 
0.9 
1.3 
1.1 
0.4 
0.8 

1.1 
2.5 
2 5 
2 6 
3.3 
2.2 
2.3 
1.3 

0.2 
0.7 

5.4 
5.0 
1.8 
2.1 
1.5 
19.5 

3.8 
3.5 
5.8 
4.0 
4.0 
13.5 
2.2 


12.2 
16.8 

6.8 
17.3 
17.6 
13.5 

7.1 
11.0 

31.5 
47.9 
45.0 
41 3 
38.1 
42.9 
42.4 
43.4 

6.2 
26.8 

69.6 
59.7 
69.8 
71.9 
54.4 
23.9 

68.7 
64.8 
62.1 
53.9 
60.4 
22.3 
36.9 


5.0 
8.8 
11.6 
5.9 
9.1 
8.1 
4.8 
6.0 

19.7 
li5.0 
29.0 
27.6 
24.8 
20.1 
37.0 
38.1 

1.2 

1.1 

2.1 
9.5 
2.7 
1.8 
4.3 
22.6 

1.9 
6.6 

12.7 
9.0 
4.6 
5.4 

43.3 


1.2 


Sorghum, fodder 


1.8 


Rye fodder 


1.8 
2.0 




2 8 


Red clover 


2 1 




1 7 




1.4 


Hay and Other Dry Coarse Fodder. 
Corn stover. 


3.4 




6.2 


Timothy hay 

Hay of mixed grasses 

Clover hay.. 


4 4 
55 
6 2 




7.5 


Oat straw 


5.1 




4.2 


Root Crops. 
Turnips 


0.8 




1.1 


Grain Crops and Other Seed. 

Corn 

Oats 

Barley 


1.5 
3.0 
2.4 


Wheat 


1.8 




3.4 


Cottonseed 


4.7 


Mill Products. 
Corn meal 


1.4 




1.5 


Corn hran 


1.3 




5.8 


Wheat middlings. . 


3.3 




7.0 


Cottonseed-hulls 


2.7 







256 



ELEMENTS OF AGKICULTURE 



Stock Foods — Continued 



Table YI 

Per Cent of Nutrients Digestible in Stock Foods 





IS 


Digestible Nutrients. 


NAME OF FOOD. 


1 

Pi 


t 


III 




Green Food and Ensilage. 
Corn fodder ■ 


6fi 
67 
74 
71 
66 
76 
64 

60 
57 
58 
61 
59 
48 
43 

93 

85 

91 
70 
86 
87 
66 

88 
79 
61 
79 

11 


53 
46 
79 
70 
67 
74 
52 

45 
48 
58 
62 
65 
30 
11 

90 
61 

76 
78 
70 
83 
68 

60 
52 
79 
82 
88 
6 


76 
74 
74 
63 
65 
59 
85 

62 
57 
48 
62 
50 
33 
31 

98 

86 
83 
89 
55 

87 

92 
84 
68 
85 
93 
79 


74 
74 
71 
73 
78 
84 
69 

61 
63 
59 
69 
71 
44 
38 

97 
90 

93 

76 
92 
94 
50 

93 
88 
69 
85 
64 
34 


52 




59 


Rve fodder 


80 




76 


Clover 


53 


Cowpea vines. 


57 


Corn ensilase 


62 


Hay and Other Dry Coarse Fodder. 
Corn stover 


67 




52 




60 




49 


Cowpea vine hay 


43 
54 


Wheat straw 


52 


Eoot Crops. 
Turnips 


100 


Potatoes 




Grain Crops and Other Seed. 
Corn 


58 


Oats 


20 


Barley 


50 




26 




76 


Mill Products. 






45 


Wheat bran 


22 


Wheat middlings 


36 


Cottonseed-meal 


32 


rjn t.tnii sppd-hnll65 


47 







APPENDIX 



257 



Stock Foods— Continued 



Table YII 

Average of Digestible Nutrients and Fertilizing Constituents 
in Stock Foods 



NAME OF FOOD. 



ft 



Digestible 

Nutrients in 100 

Pounds. 



6^ 



Fertilizing 

Constituents in 

100 Pounds. 



S-1 



Green Food and Ensilage. 

Corn fodder 

Sorjfhum fodder 

Rye fodder 

Kentucky bluegrass 

Red clover 

Cowpea vines 

Corn ensilage 

Hay and Other Dry Coarse 
Fodders. 

Corn stover 

Timothy hay 

Hay of mixed grasses 

Red clover 

Cowpea vine hay 

Oat straw 

Wheat straw 

Foot Crops. 

Turnips 

Potatoes 

Grain and Other Seed. 

Corn 

Oats 

Barley. 

Cowpeas 

Cottonseed 

Mill Products. 

Corn meal 

Corn and cob meal 

Wheat bran 

Wheat middlings 

Cottonseed-meal 

Cottonseed-hulls 



20.7 


1.0 


0.4 


11.6 


0.30 


0.15 


30.6 


0.7 


1.2 


17.6 


0.30 


0.09 


23.4 


2.1 


0.4 


14.1 


0.53 


0.25 


34.9 


3.0 


0.8 


19.8 






'29.2 


2.9 


0.7 


14.8 


0.54 


0.15 


16.4 


1.8 


0.2 


8.7 


0.27 


0.10 


20.9 


0.9 


0.7 


11.3 


0.28 


0.10 


59.5 


1.7 


0.7 


32.4 


1.10 


0.29 


86.8 


2.8 


1.4 


43.4 


1.00 


0.50 


87.1 


5.9 


1.2 


40.9 


1.40 


0.27 


84.7 


7.6 


2.0 


38.4 


2.00 


0.38 


89.3 


10.8 


1.1 


39.0 


2.66 


0.52 


90.8 


1.2 


0.8 


38 6 


0.46 


0.28 


90.4 


0.4 


0.4 


36.3 


0.60 


0.22 


9.5 


1.0 


0.2 


6.1 


0.19 


0.09 


31.6 


1.2 




24.1 


0.24 


0.08 


89.1 


8.0 


4.6 


65.9 


1.58 


0.57 


89.0 


9.2 


4.2 


47.3 


1.65 


0.69 


89.1 


8.7 


1.6 


65.6 


1.51 


0.79 


87.8 


20.0 


0.8 


53.2 


3.87 


0.82 


90.1 


13.2 


16.9 


29.1 


3.10 


1.05 


85.0 


5.5 


3.5 


63.8 


1.58 


0.63 


84.9 


4.4 


2.9 


60.0 


1.41 


0.57 


88.1 


12.2 


2.7 


39.2 


2.67 


2.89 


87.9 


12.8 


3.4 


53.0 


2.63 


0.95 


91.5 


38.1 


12.6 


16.0 


6.90 


3.00 


89.5 


0.3 


1.7 


32.9 


0.69 


0.25 



0.30 
0.25 
0.70 

6^40 
0.30 
0.37 



1.40 
1.41 
1.55 
2.20 
1.47 
1.77 
0.63 



0.34 
0.37 



0.37 
0.48 
0.48 
0.99 
1.09 



0.40 
0.47 
1.61 
63 
1.50 
1.02 



258 



ELEMENTS OF AGKICULTUKE 



Stock Foods— Continued 



Table VIII 
Pcunds of Food Required Per Day for 1,000 Pounds Live Weight 



KIND OF ANIMAL. 



Digestible 


Nutrients. 








c 




62 






r^ CS 








o 


U^ 


o1 


0.7 


0.1 


8.0 


2.0 


0.5 


11.5 


2.7 


0.6 


15.0 


2.5 


0.5 


12.0 


1.5 


0.3 


11.0 


3.0 


0.6 


15.0 


1.8 


0.6 


11.0 


2.5 


0.8 


13.3 


4.0 


0.5 


24.0 


4.0 


2.0 


13.8 


3.0 


1.0 


13.5 


2.5 


0.6 


13.5 


2.0 


0.4 


13.0 


1.5 


0.3 


12.0 



Oxen at rest in stall 

Oxen at moderate work 

Fattening cattle 

Milch cows «. 

Sheep, wool growing. . . 

Sheep, fattening 

Horses, moderate work 

Horses, hard work 

Swine, fattening 



Growing Cattle. 

Age in 
months. 



Average live 

wt. per head. 

Lbs. 



2-3 150 

3-6 300 

6-12 500 

12-18 700 

18-24 850 



11.8 
6.5 
6.1 
5.3 
7.8 
5.5 
6.9 
6.0 
6.3 



4.7 
5.3 

6.0 
7.0 
8.5 



A1»PENDIX 



259 



Stock Poods— Continued 



Table IX 

Legal Weights of Grain, Seed, Etc. — Pounds Per Bushel Required 
by Law or Custom 







i 




^ 


'6 

a; 




























I 


"3 






m 








>> 


STATES. 


§? 


M 
S 


(1< 






c 

O 


CC 


2 




i 




5 

o 
























^ 


t-i 


H 




OS 


0^ 


S 




o 


o 


c 




o 


i^ 


s 




M 


m 


PQ 


O 


o 


o 


O 


o 


P-, 


tf 


^ 


H 


H 


New York 


48 


62 


48 


60 


58 






32 


60 


56 


60 




44 


New Jersey 


48 




50 


64 


56 




57 


30 


60 


56 


60 




45 


Pennsylvania... . 


47 




48 


62 


56 


48 


50 


30 


80 


56 


60 






Delaware 










56 


48 










60 






Maryland 




62 












26 


56 


56 








Dis. of Columbia 


47 


62 


48 


60 


56 


48 


57 


32 


56 


56 


60 


55 


45 


Virginia 


48 


60 


5'^ 


64 


56 


50 


57 


H'^ 


60 


56 


60 


56 


45 


West Virginia . . . 


48 


60 


52 


60 


56 






32 


60 


56 


60 


.. 


45 


North Carolina. . 


48 




50 


64 


54 


46 




30 




56 


60 






South Carolina.. 


48 


60 


56 


60 


56 


50 


57 


32 


60 


56 


60 






Georgia . 


47 
48 
47 
48 


60 
GO 
60 


52 
48 
48 


60 
60 
60 
60 


56 
56 
56 
56 


48 
48 

48 
48 


57 
57 
57 


32 
32 
32 
32 


60 

,60 

60 

60 


56 
56 
56 
56 


60 
60 
60 
60 


55 
55 
55 


45 


Florida 


45 


Alabama . 


45 


Mississippi 


45 


Louisiana 










56 


50 




32 












Texas 


48 


60 


42 


60 


56 




57 


32 


60 


56 


60 


55 


45 


Arkansas 


48 


60 


52 


60 


56 


48 


57 


32 


60 


56 


60 


57 


60 


Tennessee 


48 


60 


50 


60 


56 


50 


56 


32 


60 


56 


60 


50 


45 


Kentucky 


47 


60 


56 


60 


56 


50 


57 


32 


60 


56 


60 


60 


45 



Note.— Tables I to VIII, are compiled from data published in the Year, 
books of the U. S. Dept. Agr.,and from other sources. 



INDEX 



Page. 

Acid phosphate , 141 

Acid soils 115 

Aeration of soils 124 

Agriculture, Primary object of 151 

Air, Composition of 24 

Extent of 23 

In the soil 124, 126 

Necessary for germination 35 

Necessary for growing roots 61 

Solids in 30 

Albuminoids 47 

Aluminum 81 

Ammonia, Definition of 26 

In the air 28, 61 

Loss of, from manure 131 

Sulphate of 134 

Animals, Care of 190-194 

Composition of 181-185 

Food of 186-189, 214-217 

Growth of 186, 187 

How to feed 188, 195-197 

Pasturing 196, 197 

Animals 33 

Apatite 138 

Apparatus for germinating seed 37 

Ash, Estimation of 200 

Ashes, Of animal bodies 184 

Of plants 46, 50 

Of wood 129 

Atmosphere. See Air. 

Bacteria, In air 31 

In manure 130, 131 

In soils 70, 79, 95-98 

Boneyard manure 129 

Bean plant 35 

Biennials 33 

(261) , 



262 ELEMENTS OF AGKICULTUKE 

Page. 

Birds, And cultivated crops 230, 231 

Destruction of 218 

Harm by 230 

Insectivorous 222-227 

Seed-eating 228-231 

Value of 219-221 

And weeds 228, 229 

Birds of Prey, Harm by 233 

Prejudice against 232, 233 

Value of 234 

Blood, Dried 135 

Bone phosphate 50, 84, 141 

Bones 135, 181 

Breathing tiO 

Calcium, Properties of 52 

In soils 84 

Phosphate 50 

Carbohydrates 48 

Carbon, Properties of 26 

Sources of, in plants 60 

Carbon Dioxide, Formation of 26 

In the air 28, 60 

Cellulose 48 

Cereals 157 

Chile saltpetre 133 

Chlorophyll 43, 58, 65 

Chlorine 51 

Clay ...» 80 

Clouds 12 

Clovers 96, 157, 166-168 

Composting 131 

Compounds, Definition of 24 

Manufactured in plant 64 

Cendensation 11 

Corn, Meaning of word 158 

Germination of seed 36 

Roots of plant 40 

As a crop 159 

Cotton, Asa crop 174 

Cottonseed-meal 134 

Cows, Treatment of 192 

Cowpeas 146, 167 

Crops, Cereals 157 

Classification of 157 

Cultivation of 125 

Fodder 160, 164 

Cultivation 117 



INDEX 263 

Page. 

Dentrification 108 

Deserts 101 

Dew 29 

Digestion, Coefficients of 206 

Definition of 198 

Experiments 204 

Drains 119 

Drainage 118 

Dried Blood. See Blood. 
Drj- Fodder. See Fodder. 

Drj' Matter, Of animals 182 

Of plants 46 

Dust 30 

Elements 24 

Embi\vo 35 

Ensilage 160-163 

Erosion 18 

Evaporation, Definition of ^ 11 

As a temperature regulator 21 

Surface 103 

Fall plowing 124 

Farming, General and special 152 

Fat, Crude, Estimation of 200 

Feeding standards 209-212 

Tests 208 

Feldspars 84 

Fertility of soils 100 

Fertilizers, Definition of 133 

Manufacture of 140 

Nitrogenous 133 

Phosphatic 137 

Potassic 136 

Valuation of 142-144 

Fiber, Crude, Estimation of 201 

Film moisture 89 

Fish scrap 136 

Fodders, Classification of 160 

Corn 164 

Definition of 160 

Dry, coarse 164 

Green 160 

Pulled 164 

Fogs 12 

Forestry 238-242 

Forests, As a crop 240 

Destruction of 239 

Value of 238 



264 



ELEMENTS OF AGRICULTURE 



Page. 

Free water in soils 90 

Frost 29 

Gases 14 

Germination 37, 153 

Glaciers 73 

Grain crops 157-159 

Grasses 1G5 

Green Fodder. See Fodder. 

Manure 146 

Ground water 91 

Gypsum 129 

Hail 12 

Hard pan 122 

Hard water 20 

Hawks. See Birds of Prey. 

Hay, Classes of 165 

Curing 166 

Of grasses 165 

Of legumes 166-168 

Time for cutting 166, 168 

Heat : 10 

Herbivorous animals 196 

Humates 114 

Humus 70, 79, 107, 111, 113, 114, 115 

Hydrogen 26 

Indian Corn. See Corn. 

Inorganic matter of soils 70, 79 

Insects, Damage by 222 

Eaten by birds 223-225 

Irish potato 173 

Iron, Properties of 52 

In soils 85 

Iron and aluminum phospliate 84 

Irrigation 118, 119 

Kainit 136 

Kaolin 81 

Land 67 

Land plaster 120 

Leaching 19 

Leaves 42 

Leguminosse Plants, Fixation of nitrogen by 96 

For hay 166 

For manure 146 

Life in the soil 115 



INDEX 265 

Page. 

Light, E£tect on plant Itj 

Lime, Formation of 52 

Jn soils 85, 86, 114, 115 

Limestone soils 85 

Liquids 14 

Loamy soils 74 

Lye 51, 52 



Magnesium 52 

Manganese 52 

Manures, Barnyard 129 

Classification of 128 

Definition of 128 

General 145 

Green 146 

Natural 128 

Purpose of '. 145 

Special 145, 148, 149 

Stable 130 

Use of 145-149 

Marl 128 

Meteors 19 

Meteorologj' 31 

Mineral matter of plants 46 

Composition of 50 

Sources of 57, 63 

Mineral matter of soils 08, 71, 79 

Loss of, by cultivation 110-115 

Mississippi River 22, 239 

Mist 12 

Mixtures 25 

Moisture, In air 29 

In plants 45, 55, 56, 57, 63 

In soils 78, 83, 88-93, 100-105, 118-120, 124 

Effect on temperatures 29, 30 

Estimation of 200 

Mold 31 

Muck 120 

Mulch 104 

Muriate of Potash. See Potash. 

Nile River 120 

Nitrate of soda 133 

Nitrification 95 

Nitrogen, Free extract 201 

Properties of 26 

IB the air 24, 26 

In plants 46, 47, 57, 62 



266 



ELEMENTS OF AGRICULTURE 



Page. 

Nitrogen in Soils, Importance of 94 

Sources of 04, 98, 106 

Forms of 98 

Necessity of 106 

Loss of lOG, 108 

Nitrogenous Matter. See Protein. 

Non-Nitrogenous Matter, In Plants 48 

In animals 184 

Estimation of 201 

Nutrients 202 

Nutritive ratio 209 

Oats, As a crop 157, 158 

Roots of 41 

Organic matter of plants 46 

Of soils 70, 78, 79, 80, 94, 95, 98, 106, 107 

Organs of plants 38 

Owls. See Birds of Prey. 

Oxidation 25 

Oxygen in air 24, 25 

Properties of 25 

In soils 61, 124 

Pastures, Classes of 168 

Permanent 168, 169 

Temporary 169, 170 

Peaty soils 74 

Perennials 33 

Phosphates, In plants 50, 58 

In soils 83, 110-113 

In fertilizers 133, 138-143 

Phosphate Rock, Where found 138 

Appearance of 139 

Composition of 139 

Phosphoric acid 51 

Phosphorus, Properties of 50 

In soils 83, 110 

In fertilizers 133 

In phosphate rock 139 

Plants, Classes of 33 

Seed of 33, 34, 35 

Parts of 38-43 

Composition of 45-53 ^ 

Food of 55-62 * 

Growth of 63-66 

Plant food 58 

Plowing 122, 125 



INDEX 26T 

Potassium, Properties of 51 

In plants 51, 58 

In soils 84, 113, 114 

In fertilizers 133, 136, 137 

Protein, In plants 46, 47, 65 

Properties of 47 

In animals 183, 199, 200 

In foods 200 

Quartz 80 

Quick lime 52 

Radiation 15 

Radish plants 41 

Rain, Formation of 12 

Work of 18-21 

A robber 20 

Ratio, Nuti'ation. See Nutritive. 

Rations for Animals 208-213 

Compounding 209-212 

Weigliing 204, 205 

Rice as a crop 157 

Roads, Interest in 243 

Formation of 243 

Of dirt 244 

Location of 244 

Of stone 246 

Macadam 246 

Telford 246 

Value of 247 

Cost of hauling over 249 

Rocks 67 

Root crops 172 

Root hairs 40, 41 

Roots 39-42 

Rotation of crops 177 

Benefits of 177-179 

Example of 179, 180 

Salsify 39 

Salt, In the soil 19 

Not a food 199 

Sand 80 

Sap 65 

Sediment 18 

Seed 33 

Sprouting of .34-37 

Testing 151-155 

Selection of 152 

Purity of 152 



26B ELEMENTS OF AGRICULTURE 

Page. 

Seed, Germination tests of 153 

Necessity for testing 153 

Adulteration of 153 

Cost of 154 

Deterioration of 155 

Seed leaves 35 

Silage. See Ensilage. 

Silica ' 80 

Silicates 51, 84 

Silicon 51 

Silo 160 

Snow 12 

Sod 168 

Sodium 51 

Carbonate of 52 

Soft Water. See Water. 

Soiling 160 

Soils, Definition of 67 

Formation of 68-70 

Organic matter in 70, 78, 79 

Transported 72 

In place 73 

Classified 73-76 

Sandy 74 

Clay ., 74 

Loam 74 

Light 74 

Heavy 74 

Weiglit of (5 

Warm 75 

Cold 75 

Color of 76 

Water in 78, 88-93 

Inorganic matter in 79 

Plant food in 83 

Phospliorus in 83, 110-113 

Potash in 84, 113, 114 

Calcium in 84 

Iron in 85 

Analyses of 86 

Deep 92 

Shallow 92 

Nitrogen in 94-98 

Lime in 114 

Loss of water in 100-104 

Loss of fertility 100-116 

Source of water in 102 

Surface evaporation from 103 

Loss of nitrogen in 106-108 



INDEX 269 

Page. 

Soils, Loss of mineral matter in 110-116 

Life in 115 

Cultivation of 117-125 

Air in 124 

Restoration of 145-148 

Solids, Definition of 14 

In the air 30 

Soy bean 97 

Springs 91 

Stable Manure. See Manure. 

Stables 190 

Starch 64 

Stassfurt 136 

Steam 10 

Stems 42 

Stock farming 181 

Stock Poods 198-202 

Composition of 200-202 

Cost of 216, 217 

Digestibility of 204-207 

Selection of 214-217 

Volume of 214 

Stomata 56 

Stomachs of animals 214, 215 

Stones 67 

Straw 164 

Sub-irrigation 120 

Subsoil 67 

Sugar in plants 48 

In animals 184 

Sulphur 47 

Sunlight 9 

Swamps 118 

Sweet potatoes 40, 173 

Sylvinit 136 

Tankage 135 

Taproot 39 

Terracing 126 

Thermometers 14 

Tobacco 174 

Transportation 56 

Tuber crops 172-174 

Tubercles 96, 97 

Under-drains 119 

Veins of leaves 43 

Velocity of heat and light 46 

Ventilation of stables 190 



270 ELEMENTS OF AGRICULTURE 

Page. 

Volatile matter of plants 46 

Of animals 183 

Water 26 

Vapor of 29 

In plants 55, 56, 63 

Mechanical action of, on soils 68 

Chemical action of, on soils 69 

Transports soils 72 

In soils 75, 78, 88, 93, 118, 120 

Lack of, in soils .100-105 

In animal bodies 182 

For stock 195 

Water table 91 

Weeds, Destruction of 228 

Wells 91 

Wheat 157-159 

Winds 15 

Wood ashes 129 

Wood's mold 129 



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